JP2002264161A - Method for producing resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a resin film excellent in appearance. SOLUTION: When a thermoplastic resin composition is rolled and molded into a film at least with the use of a pair of rolling rolls R1 and R2, the molding is done under the conditions of 3×9.8<=P and 3×9.8×10<-6> <=P/(R/H<2> )<=2×9.8×10<-5> [P is linear pressure (kN/m); R is the peripheral speed (m/sec) of a rotational molding tool; H is the thickness (m) of the resin film after rolled].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin film, and more particularly, to a method for producing a thermoplastic resin film having a good appearance.

[0002]

2. Description of the Related Art Conventionally, a thermoplastic resin film is produced by a T-die molding method in which a molten resin is extruded into a thin film form from a wide slit die, a so-called T die, or a resin is formed into a tube from a die slit such as a ring die. An inflation molding method is known in which a tubular film is formed while being extruded into a shape and flattened with two plates while cooling.

[0003]

However, when the above method is carried out using a resin having a high molecular weight, a resin having a high melt viscosity, or a resin having a low melt elongation, defects such as pores are likely to occur, and the film appearance deteriorates. In particular, in the case of a film having a thickness of 200 μm or less, remarkable poor appearance was observed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a manufacturing method capable of obtaining a resin film having an excellent appearance.

[0005]

In order to solve the above-mentioned problems, a method for producing a resin film according to the present invention comprises a thermoplastic resin material containing a thermoplastic resin by using at least a pair of rotary molding tools. Is roll-formed under the following condition 1 to produce a resin film.

(Condition 1) 3 × 9.8 ≦ P and 3 × 9.8 × 10 ⁻⁶ ≦ P / (R / H ² ) ≦ 2 × 9.8 ×
10 ^-5 where P is the linear pressure (kN / m), R is the peripheral speed of the rotary forming tool (m / sec), and H is the thickness (m) of the resin film after rolling.

[0007] The linear pressure refers to a value obtained by dividing a pressing force acting between a pair of rotary forming tools (a position where a gap is narrowed) by a width of a film-like material obtained by pressing. As a result of intensive studies, the inventors of the present invention have found that by setting the conditions as described above, it is possible to obtain a resin film-like material in which holes, defects, and the like are less likely to occur. As a result, a resin film having an excellent appearance was obtained.

[0008] As a preferred embodiment of the present invention, there is an embodiment in which the surface temperature T of the rotary forming tool used for the roll forming is set so as to satisfy the following conditions.

(Conditions) When the thermoplastic resin is crystalline T> Tm When the thermoplastic resin is not crystalline T> Tg where Tm is the melting point of the thermoplastic resin and Tg is the glass transition point of the thermoplastic resin. .

In the present invention, "the thermoplastic resin is crystalline" means that the resin shows clear crystallinity in X-ray diffraction, and more specifically, the resin obtained by wide-angle X-ray diffraction. Has a crystallinity of 10% or more. Further, “the thermoplastic resin is not crystalline” means that the crystallinity of the resin determined by wide-angle X-ray diffraction is 10%.
Means less than. This definition applies to a single resin or a mixed resin.

According to this structure, even a resin material having a high melt viscosity and a low melt elongation, for example, a thermoplastic resin composition containing a long molecular chain polyolefin resin, has excellent surface smoothness and is beautiful. A resin film having high film thickness accuracy can be manufactured.

If the above condition regarding the surface temperature T of the rotary forming tool is not satisfied, holes are formed in the formed film-like material, or the resin is solidified before or during the rolling, so that the film cannot be formed by roll forming. And the like are not preferred.

Examples of the thermoplastic resin material include a single type of thermoplastic resin, a composition comprising two or more types of thermoplastic resins, and a composition comprising one or more types of thermoplastic resins and one or more types of additives. The thermoplastic resin contained in the thermoplastic resin material, ethylene, propylene, butene,
A polyolefin resin which is a homopolymer of an olefin such as hexene or a copolymer of two or more olefins, and a copolymer of one or more olefins and one or more polymerizable monomers polymerizable with the olefin; Acrylic resin such as methyl acrylate, polymethyl methacrylate, ethylene-ethyl acrylate copolymer, butadiene-styrene copolymer, acrylonitrile-styrene copolymer, polystyrene, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene Copolymer, styrene resin such as styrene-acrylic acid copolymer, vinyl chloride resin, polyvinyl fluoride resin such as polyvinyl fluoride, polyvinylidene fluoride, 6-nylon, 6,6-nylon, 12-nylon Amide resins such as polyethylene, polyethylene Saturated ester resins such as phthalate and polypributylene terephthalate, polycarbonate, polyphenylene oxide, polyacetal, polyphenylene sulfide, silicone resin, thermoplastic urethane resin, polyetheretherketone, polyetherimide, various thermoplastic elastomers, or crosslinked products thereof And the like.

When a polyolefin resin is used among the above thermoplastic resins, the formed film-like material is excellent in recyclability and solvent resistance, and does not generate dioxin and the like even when incinerated, thus deteriorating the environment. Polyolefin resins can be particularly preferably used because they do not occur.

The olefin constituting the polyolefin resin includes ethylene, propylene, butene, hexene and the like. Specific examples of the polyolefin include low-density polyethylene and linear polyethylene (ethylene-α-
Olefin copolymer), polyethylene resins such as high-density polyethylene, polypropylene, polypropylene resins such as ethylene-propylene copolymer, poly (4-methylpentene-1), poly (butene-1) and ethylene-
And vinyl acetate copolymer.

As a result, according to the present invention, it is possible to form a film even from a resin material having a high melt viscosity and a low melt elongation, for example, a resin material having difficulty in molding such as a thermoplastic resin composition containing a long molecular chain polyolefin resin. It was possible to provide a method capable of manufacturing a resin film having high thickness accuracy.

In the present invention, the term "film-like material" is used as a concept including not only a film originally, but also a somewhat thick sheet-like material. It is a generic term for thin-shaped objects.

In another preferred embodiment of the present invention, the thermoplastic resin contains at least 10% by weight of a thermoplastic resin having a molecular chain length of 2850 nm or more (referred to as a long molecular chain thermoplastic resin in the present invention). Is raised.

Since a long-chain thermoplastic resin having a molecular chain length of 2850 nm or more is particularly excellent in strength, the thermoplastic resin contains such a long-chain thermoplastic resin in an amount of 10% by weight or more, more preferably 20% by weight or more. By doing so, a film-like material having remarkably excellent strength is obtained, and the film-like material thus obtained can be used for various purposes. When the long molecular chain thermoplastic resin is contained in an amount of 30% by weight or more, a film having higher strength can be obtained. The molecular chain length, weight average molecular chain length, molecular weight and weight average molecular weight of the thermoplastic resin are measured by GPC (gel permeation chromatography), and the content of the thermoplastic resin in a specific molecular chain length range or a specific molecular weight range is measured. (% By weight) can be determined by integrating a molecular weight distribution curve obtained by GPC measurement.

In still another preferred embodiment of the present invention,
In one embodiment, the thermoplastic resin material contains 10 to 300 parts by weight of a filler based on 100 parts by weight of the thermoplastic resin.

When the thermoplastic resin material contains 10 to 300 parts by weight of the filler with respect to 100 parts by weight of the thermoplastic resin, the conventional processing method has problems such as melt fracture or porosity in the form of a sump. Occurred, a film with good film thickness accuracy could not be obtained, but according to the method of the present invention, not only a film having good film thickness accuracy was obtained,
The rigidity of the obtained film is excellent. If the content of the filler is less than 10 parts by weight, it is insufficient to improve the rigidity, and if it exceeds 300 parts by weight, the effect of improving the rigidity is low because of the content, which is not preferable.

As the filler, inorganic and organic fillers are used. For example, as the inorganic filler, calcium carbonate, talc, clay, kaolin, silica, hydrotalcite, diatomaceous earth, magnesium carbonate, barium carbonate, calcium sulfate, Magnesium sulfate, barium sulfate, aluminum hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, titanium oxide, alumina, mica, zeolite, glass powder, zinc oxide and the like can be used.

As the organic filler, various resin particles can be used. Preferably, styrene, vinyl ketone, acrylonitrile, methyl methacrylate, ethyl methacrylate, glycidyl methacrylate, glycidyl acrylate, methyl acrylate or the like is used alone or in combination. Particles such as polymers of more than one kind, and polycondensation resins such as melamine and urea are exemplified.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Structure of Production Line> FIG. 1 is a schematic diagram showing a production line for producing a porous film. This production line is composed of kneading step 1, rolling step 2, first slitting step 3, stretching step 4, and second slitting step 5 in the order of the steps.

In the kneading step 1, a screw kneading apparatus 10
This kneading apparatus includes a first hopper 11 for supplying a mixed resin and a second hopper 12 for supplying a filler. The screw kneading apparatus 10 includes a biaxial screw 13 and extrudes the mixed resin and the filler supplied from the hoppers 11 and 12 forward while strongly kneading them. The resin composition obtained by kneading is pelletized.

In the rolling step 2, a screw extruder 20 is used. A hopper 2 into which pellets of the resin composition obtained in the kneading step 1 are charged
1 and a screw 22. The resin composition is extruded forward by this device 20, discharged in a rod shape or a sheet shape by a die 23, and discharged by a rolling roll mechanism 24.
To obtain a rolled film.

In the first slitting step 3, the rolled film obtained in the rolling step 2 is cut in two in the width direction, and for example, two 300 mm wide films are obtained from a 600 mm wide film.

In the stretching step 4, a film having a width of, for example, 300 mm is stretched 4 to 5 times in the width direction under a predetermined temperature condition. Thereby, pores on the order of submicrons are formed, and a porous film can be obtained.

In the second slitting step 5, the obtained porous film is cut into a desired width.

<Structure of Extruder> Next, rolling process 2
The configuration of the screw extruder and the rolling roll mechanism 24 used in the above will be described with reference to FIG.

That is, a thermoplastic resin or a thermoplastic resin composition containing a long-chain thermoplastic resin, or a mixture of the thermoplastic resin composition and a filler, and in some cases, a nonionic surfactant may be used. The components are adjusted in advance (hereinafter, the adjusted product may be simply referred to as a resin composition) in accordance with the above. To sufficiently knead the mixture, a roll-type or Banbury-type kneader or an extruder can be used. FIG. 2 shows an example in which a screw-type extruder 20 is used. The extruding device 20 extrudes the resin composition forward while strongly kneading it, and discharges the resin composition into a rod or sheet shape by a die 23 and passes the resin composition between a pair of rolling rolls R1 and R2. The surface temperature of the pair of rolling rolls R1 and R2 is set to a temperature T that satisfies the above-described conditions, and the pair of rolling rolls R1 and R2 is rotated at a substantially constant speed by a control device (not shown). By controlling the pair of rolling rolls R1 and R2 in this manner, it is possible to finish the surface of the rolled film smoothly and beautifully.

The surface temperature of the rolling rolls R1 and R2 is maintained at a temperature higher than the melting point or the glass transition point of the resin composition. In this case, the melting point is determined by DSC (differential scanning calorimetry).
When there are a plurality of peaks, the peak temperature having the largest heat of fusion ΔH (J / g) is defined as the melting point. The rate of temperature rise when measuring the melting point can be 5 ° C./min.

The glass transition temperature Tg is set at a frequency of 110H.
This is the temperature at the peak apex of the loss elastic modulus E ″ in the viscoelasticity measurement as z. When there are a plurality of peaks, the temperature at the peak apex on the high-temperature side is Tg. In order to set to, a heater may be installed inside the roll, heating water or steam may be supplied,
The periphery of the roll may be externally heated, and the method is not particularly limited.

Then, the resin composition rolled by the pair of rolling rolls R1 and R2 is formed into a film F, and then the resin composition is rotated at a somewhat higher speed than the rolling rolls R1 and R2.
The fine wrinkles generated in the film F are extended by the roll R3, and further, the fourth roll R4, the fifth roll R5, and the sixth roll R5.
It is taken up by the take-up roll 25 via the roll R6. The peripheral speed of each of the rolls R4, R5 and R6 is preferably controlled to be equal to or slightly higher than the peripheral speed of the third roll R3. Is more smooth and beautiful.

The molecular chain length, weight average molecular chain length, molecular weight and weight average molecular weight of the polyolefin are measured by GPC, and the content (% by weight) of the polyolefin in the specific molecular chain length range or the specific molecular weight range is obtained by GPC measurement. It can be determined by integrating the obtained molecular weight distribution curve. In many cases, the solvent used in the GPC measurement is o-dichlorobenzene, and the measurement temperature is 140 ° C.

The roll forming method using the manufacturing apparatus 20 shown in FIG.
Even when rolling to the following thickness, a film can be obtained with a high thickness accuracy of about ± 2% or less.
Of course, a resin composition that is easy to mold can be very easily and accurately formed into a thin film.

The method of supplying the resin composition to the rolling roll mechanism 24 is not particularly limited, and a T-die is attached to the die 23 at the tip of the extruder 20.
A preformed body having a thickness of about several mm to several cm can be formed and supplied by the T-die forming method.

In the production of the film-like material, the thermoplastic resin material to be used includes other components such as a fatty acid ester, a stabilizer, an antioxidant, an ultraviolet absorber, and a flame retardant as long as the object of the present invention is not hindered. Additives may be added.

<Rolling forming conditions> Next, the rolling roll mechanism 24
Preferred conditions for roll forming are described below. FIG. 3 is an enlarged view showing a pair of rolling rolls R1 and R2. The rolls R1 and R2 receive the supply of the resin composition from the extruder 20 and form the film F. Roll Roll R
1 and R2 are rotated in the direction indicated by the arrow to
The resin composition is roll-formed.

A pressing force acts on the resin composition P along a straight line connecting the rotation axes of the rolling rolls R1 and R2.
This pressing force is at the position where the gap between the rolling rolls is the narrowest,
Assuming that the pressure acts, the linear pressure P is obtained by dividing the pressing force by the width of the film obtained by the pressing.
The linear pressure is defined as P (kN (kilo Newton) / m), the thickness of the film F after rolling is defined as H (m), and the rolling roll R
The present inventors have found that when the peripheral speed of R1 and R2 is R (m / sec), a film having a good appearance can be obtained by performing roll forming under the following conditions.

(Conditions) 3 × 9.8 ≦ P 3 × 9.8 × 10 ⁻⁶ ≦ P / (R / H ² ) ≦ 2 × 9.8 ×
FIG. 4 is a graph showing the above 10 ^-5 relationship.

In FIG. 4, the vertical axis (y-axis) represents P / 9.8, and the horizontal axis (x-axis) represents (R / H ² ) /9.8. As a result of experiments conducted by changing the linear pressure conditions, the inventors found that in the region below the straight line y = 3 × 10 ⁻⁶ x, the film had cracks and a poor appearance in which a drip-like pattern appeared on the surface. It was found to occur.

It was found that in the region above the straight line y = 2 × 10 ⁻⁵ x, poor appearance such as cracks in the film and unevenness on the surface was generated. In addition, it was found that in the region sandwiched between the straight lines y = 3 × 10 ⁻⁶ x and the straight lines y = 2 × 10 ⁻⁵ x, and P ≧ 3, the appearance defect did not occur. did.

When the linear pressure in the above conditional expression is expressed in units of ton, (condition) 3 × ≦ P 3 × 10 ⁻⁶ ≦ P / (R / H ² ) ≦ 2 × 10 ⁻⁵

[0045]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. First, a description will be given of a measuring method, a measuring device, and the like used.

[Melting tension] Capirograph 1B PC-98 manufactured by Toyo Seiki Seisaku-sho, Ltd.
Using 01VM, diameter D = 2.095mm, length L = 1
Use a 4.75 mm orifice. First, a resin at a predetermined temperature is extruded at a speed of 5 mm / min, and the take-up speed is changed to take out the resin. The melt tension at this maximum take-off speed is the melt tension at that temperature.

[Extension] As a measuring device, Capirograph 1B PC-980 manufactured by Toyo Seiki Seisaku-sho, Ltd.
Using 1VM, diameter D = 2.095mm, length L = 1
Use a 4.75 mm orifice. First, the resin is extruded at a predetermined temperature at a speed of 5 mm / min, and the resin diameter D
₁ Find (mm) _. Next, the resin is taken up by changing the take-up speed, and the diameter D ₂ of the resin when the resin is cut.
(Mm) and the degree of elongation is determined by the following equation.

[0048] Using the elongation ^{_{(%) = (D 1 2}} -D 2 2) / D 1 2 × 100 Waters Co. gel permeation chromatograph AllianceGPC2000 type as [the molecular weight measurement] measurement device. Other conditions are shown below.

Column: Tosoh TSKgel GMH _HR
H (S) HT 30 cm × 2 GMH ₆ HTL 30 cm × 2 Mobile phase: o-dichlorobenzene Detector: Differential refractometer Column temperature: 140 ° C. Flow rate: 1.0 mL / min Injection volume: 500 μL 30 mg of sample is 145 in 20 mL of o-dichlorobenzene
After complete dissolution at ℃, the solution was adjusted to a pore size of 0.45 μm
And the filtrate was used as a feed solution.

The calibration curve was prepared using 16 kinds of standard polystyrenes having known molecular weights. Polystyrene Q
41.3 was used as a factor.

[Film Thickness Measurement] The thickness of the obtained film was measured by an off-line sheet thickness meter (TO
Using F2 Var 3.22), it was determined by measuring a plurality of points in the width direction and the length direction.

The average value of all the measured values was calculated, and the ratio (positive sign) of the difference between the maximum value and the average value in the measured values to the average value was calculated. Furthermore, the ratio (minus sign) of the difference between the minimum value and the average value in the measured values to the average value was calculated. The thickness accuracy is indicated by these ratios.

Example 1 Long molecular chain polyethylene powder 7
0% by weight (HIZEX Million 340M, manufactured by Mitsui Chemicals, Inc., weight average molecular chain length: 17000 nm, weight average molecular weight: 3,000,000, melting point: 136 ° C.), 30% by weight of low molecular weight polyethylene powder (Hi Wax 110P, Mitsui Chemicals, Inc.) (Weight average molecular weight: 1000, melting point: 110 ° C.) in a biaxial kneader.
120 parts by weight of calcium carbonate (Star Spigot 15A, average particle size 0.15 μm, manufactured by Shiraishi Calcium Co., Ltd.) was added to 00 parts by weight, and the mixture was melt-kneaded at 230 ° C. to obtain a resin composition. The content of polyethylene having a molecular chain length of 2850 nm or more in the resin component in this composition is 27% by weight.
Met. This resin composition is rolled with a pair of rolls rotating at a constant peripheral speed at a roll surface temperature of 149 ° C.
A μm film was prepared.

Example 2 Long molecular chain polyethylene powder 6
0% by weight (HIZEX Million 340M, manufactured by Mitsui Chemicals, Inc., weight average molecular chain length: 17000 nm, weight average molecular weight: 3,000,000, melting point: 136 ° C.), 28% by weight of low molecular weight polyethylene powder (HIWAX 110P, Mitsui Chemicals, Inc.) , Weight average molecular weight 1000, melting point 110
12% by weight of linear polyethylene (FS240 manufactured by Sumitomo Chemical Co., Ltd.) using a twin-screw kneader, and 120 parts by weight of calcium carbonate (Shiraishi) based on 100 parts by weight of the resin mixture from the middle of the extruder. Calcium Co., Ltd., Star Pigot 15A, average particle size 0.15 μm) was added and melt-kneaded at 230 ° C., and then rolled with a pair of rolls rotating at a constant circumferential speed at a roll surface temperature of 145 ° C. About 50
A μm film was prepared.

Example 3 Long molecular chain polyethylene powder 8
0% by weight (HIZEX Million 340M, manufactured by Mitsui Chemicals, Inc., weight average molecular chain length: 17000 nm, weight average molecular weight: 3,000,000, melting point: 136 ° C.), 20% by weight of low molecular weight polyethylene powder (Hi Wax 110P, Mitsui Chemicals, Inc.) , Weight average molecular weight 1000, melting point 110
) Was melted and kneaded at 230 ° C, and then rolled with a pair of rolls rotating at a constant peripheral speed at a roll surface temperature of 135 ° C to produce a film having a thickness of about 300 µm.

Comparative Example 1 The same roll as in Example 1 was used, but rolled at a roll surface temperature of 175 ° C. to produce a film having a thickness of about 300 μm.

Comparative Example 2 The same roll as in Example 1 was used, but roll-rolled at a roll surface temperature of 130 ° C. to produce a film having a thickness of about 300 μm.

Comparative Example 3 The same resin composition (including a filler) as in Example 1 was formed at a mold surface temperature of 230 ° C. by a T-die molding method. However, the obtained molded product had a large number of fractures and was in a stagnation shape, and the film thickness could not be measured.

Comparative Example 4 The same resin composition (including a filler) as in Example 1 was formed at a mold surface temperature of 230 ° C. by inflation molding. However, similarly to Comparative Example 3, the obtained molded product had a large number of fractures and was in the form of a sump, and the film thickness could not be measured.

Table 1 summarizes the results of the above Examples and Comparative Examples. As is clear from Table 1, Example 1
It can be seen that those of Nos. 1 to 3 are not only excellent in thickness accuracy but also excellent in appearance and shape as compared with those of Comparative Examples 1 to 4.

[0061]

[Table 1] <Another embodiment> The rolling roll mechanism is not limited to the one shown in the present embodiment. Further, the conditional expression can be applied to other rolling rolls.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a manufacturing process of a porous film.

FIG. 2 is a diagram showing a configuration of a screw extruder and a roll rolling mechanism.

FIG. 3 is an enlarged view of a rolling roll.

FIG. 4 is a graph showing a range of parameters for obtaining a film having a good appearance.

[Explanation of symbols]

 Reference Signs List 20 screw extruder 24 rolling roll mechanism R1, R2 rolling roll

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08L 23:00 C08L 23:00 (72) Inventor Akira Hanada 2-10-1 Tsukahara, Takatsuki-shi, Osaka Sumitomo Chemical Incorporated (72) Inventor Takeshi Yamada 2-1-1 Tsukahara, Takatsuki-shi, Osaka Sumika Plastics Tech Co., Ltd. F-term (reference) 4F071 AA15 AA81 AA84 AA86 AB21 AE17 AF21 AF43 AF54 BB04 BC01 4F204 AB11 AG01 AR02 AR09 AR12 FA06 FA07 FB02

Claims (4)

[Claims] In producing a resin film by rolling and molding a thermoplastic resin material containing a thermoplastic resin using at least a pair of rotary molding tools, the roll molding is performed under the following condition 1. (Condition 1) 3 × 9.8 ≦ P 3 × 9.8 × 10 ⁻⁶ ≦ P / (R / H ² ) ≦ 2 × 9. 8x
10 ^-5 where P is the linear pressure (kN / m), R is the peripheral speed of the rotary forming tool (m / sec), and H is the thickness (m) of the resin film after rolling. 2. The method for producing a resin film according to claim 1, wherein the surface temperature T of the rotary forming tool used for the roll forming is set so as to satisfy the following condition 2. 2) When the thermoplastic resin is crystalline T> Tm When the thermoplastic resin is not crystalline T> Tg where Tm is the melting point of the thermoplastic resin and Tg is the glass transition point of the thermoplastic resin. 3. The thermoplastic resin has a molecular chain length of 285.
The method for producing a resinous film according to claim 1 or 2, wherein the method comprises 10% by weight or more of a thermoplastic resin having a thickness of 0 nm or more. 4. The resin-made resin according to claim 1, wherein the thermoplastic resin material contains 10 to 300 parts by weight of a filler with respect to 100 parts by weight of the thermoplastic resin. A method for producing a film.