CN104149327B - Secondary blow molding method of polylactic acid film - Google Patents

Abstract

The invention discloses a secondary blow molding method of a polylactic acid film. The secondary blow molding method comprises the following steps: (a) the polylactic acid film passes through a lower traction roller A, a heating furnace A, an upper traction roller A, an upper traction roller B, a heating furnace B and a lower traction roller B in sequence; (b) upper and lower layers of heating devices A are annularly arranged in the heating furnace A, and are different in heating temperature; (c) the first inflation is performed for the polylactic acid film to form a bubble film; and the blow stretching is performed; (d) upper and lower layers of heating devices B are annularly arranged in the heating furnace B, and are different in heating temperature; and (e) the secondary inflation is performed for the polylactic acid film to form a bubble film again; and bubbles are removed through the lower traction roller B to obtain the polylactic acid film. The secondary blow molding method of the polylactic acid film enables the polylactic acid film to be slowly heated and expanded when the polylactic acid film is blown in the heating furnace A and the heating furnace B, and the polylactic acid film can be slowly cooled to mold after the expansion is finished, so that the obtained polylactic acid film has higher quality.

Description

A kind of secondary inflation forming method of polylactic acid film

Technical field

The present invention relates to the secondary inflation forming method of polylactic acid film, more particularly, to polylactic acid film.

Background technology

Polylactic acid (PLA), also known as polylactide, is a kind of degradable going out as produced in starch from Renewable resource Macromolecule polyester resin material, in addition to advantageously reducing the dependency to petroleum resources for the mankind, can be biodegradable under field conditions (factors) Carbon dioxide and water, very friendly to environment.

At present, polylactic acid film major part is to obtain via biaxial tension via after extrusion curtain coating or extrusion sheet again, Less using the flat polylactic acid film squeezing into blowing method technique, main cause be put down using inflation squeeze into blowing method technology it is difficult to Obtain the polylactic acid film with good pliability and heat stability.Squeeze into the polylactic acid film blowing using flat, its blown film temperature Must control between 140 DEG C -160 DEG C, must assure that head temperature uniformly simultaneously, and blow-up ratio can not be excessive, otherwise easily Cause film bubble unstable, make thin film that fold easily to occur.Although, tuning up draw ratio can make the longitudinal tensile strength of thin film carry High, lower thickness, but because polylactic acid matter is hard and crisp, poor ductility, its unique molecular structure lead in process with The rising of temperature, its stickiness can decline rapidly so that the thickness of thin film is difficult to control to, if draw ratio is excessive, also can be by thin film Break and cause film breakage phenomenon.Put down using inflation and squeeze into blowing method producing in polylactic acid film forming procedure, thin film laterally and vertical Required degree of drawing cannot be obtained to direction, so that polylactic acid molecule is orientated, the film crystal unity after molding is low and not heatproof, After putting out the film take-up after bubble, inner surface will mutually cohere, the mechanical property such as the tensile strength of thin film, pliability and heat stability Can be poor, lead to moulded products shrinkage factor greatly, poor dimensional stability, strongly limit development and the range of polylactic acid film.

Put down the polylactic acid film squeezing into blowing method in the market using inflation mostly only through an inflation, it is in inflation mistake Cheng Zhong, heating-up temperature is mostly single temperature, leads to temperature change during polylactic acid film inflation larger so that the poly- breast that obtains Sour thin film non-refractory and degree of crystallinity is relatively low, if after due to polylactic acid, in heating process, heating-up temperature rises sharply and can lead to put out bubble Polylactic acid film inner surface mutually coheres and leads to not do secondary inflation, and due to polylactic acid cannot be improved using secondary inflation The mechanical strength of thin film and Kekelé structure count, lead to that current moulded products shrinkage factor is big, poor dimensional stability, strongly limit poly- breast The development of sour thin film and range.

Content of the invention

The present invention is directed to that during inflation present in prior art heating-up temperature is single, temperature change big, polylactic acid film not A kind of more low defect of high temperature resistant and degree of crystallinity, there is provided the secondary inflation forming method of new polylactic acid film.

In order to solve above-mentioned technical problem, the present invention is achieved through the following technical solutions：

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. by polylactic acid film sequentially pass through lower traction rod A, heating furnace A, upper carry-over pinch rolls A, upper carry-over pinch rolls B, heating furnace B, Lower traction rod B；

B. heating furnace A annular is provided with upper and lower two-layer heater A, makes lower floor's heater A temperature control of heating furnace A , at 25 DEG C～75 DEG C, the upper strata heater A temperature control of heating furnace A is at 35 DEG C～85 DEG C for system；

C. to lower traction, the polylactic acid film between rod A and upper carry-over pinch rolls A is inflated and forms vacuolar membrane, makes the swollen of vacuolar membrane Swollen ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A and upper carry-over pinch rolls A 1～2.5, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B annular is provided with upper and lower two-layer heater B, makes the upper strata heater B temperature control of heating furnace B , at 65 DEG C～100 DEG C, lower floor's heater B temperature control of heating furnace B is at 80 DEG C～120 DEG C for system；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B and lower traction rod B is filled Gas simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction rod B through this section Obtain degree of crystallinity after putting out bubble and reach 20%～25%, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Polylactic acid film, when heating furnace A, carries out first time inflation, because heating furnace A annular is provided with upper and lower two So that the temperature in heating furnace A is in gentle curve distribution, polylactic acid film is slowly added in heating furnace A layer heater A Thermal expansion, expands molding of slowly lowering the temperature again after finishing, completes first time inflation, enter in heating furnace B, due to heating furnace after putting out bubble In B, equally annular is provided with upper and lower two-layer heater B, then polylactic acid film is slowly heated expansion in heating furnace B again, Expansion finish after more slowly lower the temperature molding, finally give the higher polylactic acid film of quality.

Preferably, a kind of secondary inflation forming method of polylactic acid film described above, in described step b, make , at 45 DEG C～55 DEG C, the upper strata heater A temperature control of heating furnace A is 55 for lower floor's heater A temperature control of heating furnace A DEG C～65 DEG C.In this temperature range, the polylactic acid film quality obtaining is higher.

Preferably, a kind of secondary inflation forming method of polylactic acid film described above, in described step d, make , at 65 DEG C～80 DEG C, lower floor's heater B temperature control of heating furnace B is 80 for the upper strata heater B temperature control of heating furnace B DEG C～95 DEG C.In this temperature range, the polylactic acid film quality obtaining is higher.

Preferably, a kind of secondary inflation forming method of polylactic acid film described above, in described step a, gather Lactic acid thin film also carries out thickness measuring through calibrator A after heating furnace A, polylactic acid film after heating furnace B, also through thickness measuring Instrument B carries out thickness measuring.

Calibrator A be used for detecting heated stove A heating after polylactic acid film thickness, thus adjust in heating furnace A plus So that polylactic acid film thickness when expanding is more uniform, calibrator B is used for detecting heated stove B heating the temperature of thermal A The thickness of the polylactic acid film of aftershaping, thus adjust heater B in heating furnace B temperature so that aftershaping poly- breast Sour film thickness is more uniform.

Preferably, a kind of secondary inflation forming method of polylactic acid film described above, described upper strata heater A, lower floor heater A, upper strata heater B, lower floor heater B are all ceramic heating plate.The hardened structure of ceramic heating is simple, Heat up rapid and temperature-compensating is fast, its thermal efficiency is high, homogeneous heating and very energy-conservation are so that the membrane quality produced is higher.

Brief description

Fig. 1 is a kind of schematic flow sheet of the secondary inflation forming method of polylactic acid film of the present invention；

Fig. 2 is the cross-sectional view of heating furnace A in the present invention；

Fig. 3 is the cross-sectional view of heating furnace B in the present invention.

Specific embodiment

1-3 and specific embodiment are described in further detail to the present invention below in conjunction with the accompanying drawings, but they are not to this The restriction of invention：

Embodiment 1

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 2

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 3

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 4

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 5

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 6

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 7

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 8

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 9

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 10

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 11

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 12

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 13

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 14

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 15

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 16

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 17

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 18

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 19

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 20

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 21

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 22

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 23

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 24

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 25

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 26

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 27

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 25 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 28

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 29

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 30

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 31

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 32

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 33

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 34

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 35

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 36

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 37

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 38

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 39

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 40

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 41

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 42

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 43

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 44

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 45

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 46

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 47

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 48

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 49

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 50

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 51

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 52

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 53

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 54

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 75 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 55

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 56

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 57

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 58

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 59

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 60

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 61

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 62

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 63

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 35 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 64

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 65

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 66

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 67

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 68

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 69

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 70

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 71

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 72

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 85 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 73

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 74

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 75

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 65 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 76

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 77

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 78

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 100 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 79

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 80 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 80

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 120 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 81

A kind of secondary inflation forming method of polylactic acid film, comprises the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A1, heating furnace A2, upper carry-over pinch rolls A4, upper carry-over pinch rolls B5, heating Stove B6, lower traction rod B8；

B. heating furnace A2 annular is provided with upper and lower two-layer heater A, makes lower floor's heater A22 temperature of heating furnace A2 Degree controls at 50 DEG C, and the upper strata heater A21 temperature control of heating furnace A2 is at 60 DEG C；

C. to lower traction, the polylactic acid film between rod A1 and upper carry-over pinch rolls A4 is inflated and forms vacuolar membrane, makes vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1, makes bubble Film puts out, through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A4, the polylactic acid film obtaining after bubble that degree of crystallinity reaches 10%～15%；

D. heating furnace B6 annular is provided with upper and lower two-layer heater B, makes the upper strata heater B61 temperature of heating furnace B6 Degree controls at 80 DEG C, and lower floor's heater B62 temperature control of heating furnace B6 is at 95 DEG C；

E. with step c identical speed ratio under, the polylactic acid film between upper carry-over pinch rolls B5 and lower traction rod B8 is carried out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B8 obtains degree of crystallinity and reaches 20%～25% after putting out bubble, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

Embodiment 82

In described step c, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 2.5, in described step e, Upper carry-over pinch rolls B5 is identical with step c with the speed ratio of lower traction rod B8.Other steps are with embodiment 1 to 81.

Embodiment 83

In described step c, by the Transmission Ratio Control of lower traction rod A1 and upper carry-over pinch rolls A4 1.75, in described step e, Upper carry-over pinch rolls B5 is identical with step c with the speed ratio of lower traction rod B8.Other steps are with embodiment 1 to 81.

Embodiment 84

In described step b, at 45 DEG C, heating furnace A2's is upper for the lower floor's heater A22 temperature control making heating furnace A2 Layer heater A21 temperature control is at 55 DEG C.Other steps are with embodiment 1 to 83.

Embodiment 85

In described step b, at 45 DEG C, heating furnace A2's is upper for the lower floor's heater A22 temperature control making heating furnace A2 Layer heater A21 temperature control is at 65 DEG C.Other steps are with embodiment 1 to 83.

Embodiment 86

In described step b, at 45 DEG C, heating furnace A2's is upper for the lower floor's heater A22 temperature control making heating furnace A2 Layer heater A21 temperature control is at 60 DEG C.Other steps are with embodiment 1 to 83.

Embodiment 87

In described step b, at 55 DEG C, heating furnace A2's is upper for the lower floor's heater A22 temperature control making heating furnace A2 Layer heater A21 temperature control is at 55 DEG C.Other steps are with embodiment 1 to 83.

Embodiment 88

In described step b, at 55 DEG C, heating furnace A2's is upper for the lower floor's heater A22 temperature control making heating furnace A2 Layer heater A21 temperature control is at 65 DEG C.Other steps are with embodiment 1 to 83.

Embodiment 89

In described step b, at 55 DEG C, heating furnace A2's is upper for the lower floor's heater A22 temperature control making heating furnace A2 Layer heater A21 temperature control is at 60 DEG C.Other steps are with embodiment 1 to 83.

Embodiment 90

In described step b, at 50 DEG C, heating furnace A2's is upper for the lower floor's heater A22 temperature control making heating furnace A2 Layer heater A21 temperature control is at 55 DEG C.Other steps are with embodiment 1 to 83.

Embodiment 91

In described step b, at 50 DEG C, heating furnace A2's is upper for the lower floor's heater A22 temperature control making heating furnace A2 Layer heater A21 temperature control is at 65 DEG C.Other steps are with embodiment 1 to 83.

Embodiment 92

In described step b, at 50 DEG C, heating furnace A2's is upper for the lower floor's heater A22 temperature control making heating furnace A2 Layer heater A21 temperature control is at 60 DEG C.Other steps are with embodiment 1 to 83.

Embodiment 93

In described step a, polylactic acid film also carries out thickness measuring through calibrator A3 after heating furnace A2, and polylactic acid is thin Film, after heating furnace B6, also carries out thickness measuring through calibrator B7.Other steps are with embodiment 1 to 92.

Embodiment 94

Described upper strata heater A21, lower floor heater A22, upper strata heater B61, lower floor heater B62 are all For ceramic heating plate.Other steps are with embodiment 1 to 92.

In a word, the foregoing is only presently preferred embodiments of the present invention, it is equal that all scopes according to the present patent application patent are made Deng change and modification, the covering scope of the present invention all should be belonged to.

Claims (5)

1. a kind of secondary inflation forming method of polylactic acid film is it is characterised in that comprise the following steps：

A. polylactic acid film is sequentially passed through lower traction rod A（1）, heating furnace A（2）, upper carry-over pinch rolls A（4）, upper carry-over pinch rolls B（5）、 Heating furnace B（6）, lower traction rod B（8）；

B. heating furnace A（2）Annular is provided with upper and lower two-layer heater A, makes heating furnace A（2）Lower floor heater A（22） Temperature control at 25 DEG C～75 DEG C, heating furnace A（2）Upper strata heater A（21）Temperature control is at 35 DEG C～85 DEG C；

C. to lower traction rod A（1）With upper carry-over pinch rolls A（4）Between polylactic acid film be inflated and form vacuolar membrane, make vacuolar membrane Expansion ratio maintains 1.2～1.3, carries out inflation stretching, by lower traction rod A（1）With upper carry-over pinch rolls A（4）Transmission Ratio Control 1～ 2.5, make vacuolar membrane through this section of preheating inflation drawing zone and through upper carry-over pinch rolls A（4）Obtain after putting out bubble degree of crystallinity reach 10%～15% poly- Lactic acid thin film；

D. heating furnace B（6）Annular is provided with upper and lower two-layer heater B, makes heating furnace B（6）Upper strata heater B（61） Temperature control at 65 DEG C～100 DEG C, heating furnace B（6）Lower floor heater B（62）Temperature control is at 80 DEG C～120 DEG C；

E. with step c identical speed ratio under, to upper carry-over pinch rolls B（5）With lower traction rod B（8）Between polylactic acid film carry out Inflation simultaneously forms vacuolar membrane again, makes the expansion ratio of vacuolar membrane maintain 1.35～1.45, preheats shaping area and through lower traction through this section Rod B（8）Obtain degree of crystallinity after putting out bubble and reach 20%～25%, heat resisting temperature is 20 DEG C～45 DEG C of polylactic acid film.

2. a kind of polylactic acid film according to claim 1 secondary inflation forming method it is characterised in that：Described step In rapid b, make heating furnace A（2）Lower floor heater A（22）Temperature control at 45 DEG C～55 DEG C, heating furnace A（2）Upper strata add Thermal A（21）Temperature control is at 55 DEG C～65 DEG C.

3. a kind of polylactic acid film according to claim 1 secondary inflation forming method it is characterised in that：Described step In rapid d, make heating furnace B（6）Upper strata heater B（61）Temperature control at 65 DEG C～80 DEG C, heating furnace B（6）Lower floor add Thermal B（62）Temperature control is at 80 DEG C～95 DEG C.

4. a kind of polylactic acid film according to claim 1 secondary inflation forming method it is characterised in that：Described step In rapid a, polylactic acid film is through heating furnace A（2）Afterwards also through calibrator A（3）Carry out thickness measuring, polylactic acid film is through heating furnace B（6）Afterwards, also through calibrator B（7）Carry out thickness measuring.

5. a kind of polylactic acid film according to claim 1 secondary inflation forming method it is characterised in that：Described upper strata Heater A（21）, lower floor heater A（22）, upper strata heater B（61）, lower floor heater B（62）It is all pottery to send out Hot plate.