CN109397676B

CN109397676B - Blow molding processing method of CPP film

Info

Publication number: CN109397676B
Application number: CN201811362405.4A
Authority: CN
Inventors: 曹玉; 毛潞
Original assignee: Chongqing Ruiting Plastic Co Ltd
Current assignee: Chongqing Ruiting Plastic Co Ltd
Priority date: 2018-11-15
Filing date: 2018-11-15
Publication date: 2020-07-24
Anticipated expiration: 2038-11-15
Also published as: CN109397676A

Abstract

The invention relates to the field of high polymer materials, in particular to a blow molding processing method of a CPP film, which comprises the following steps: the production processing method comprises the following steps: firstly, extruding a thin-walled tube: adding a PP raw material into a machine barrel of an extruder, rotating, extruding, stirring and pushing the PP raw material by a screw, and finally extruding the PP raw material into a thin-walled tube by a right-angle head, wherein the compression ratio of the screw is 2.8-4.0, and the extrusion temperature of the right-angle head is 200-; secondly, blowing the thin-walled tube into a thin-film tube: the thin-wall tube is blown into a film tube by compressed air; thirdly, cooling and shaping the film tube: cooling the film tube by adopting a mode of firstly air cooling and then water cooling; fourthly, clamping the film tube: the thin film tube is clamped flat through two rotating belt lines in the shape of an inverted V; fifthly, drawing and winding the film tube: the clamped film tube is pressed tightly by a traction roller and then enters a winding device through a guide roller. The invention is used for solving the problems that the film tube is unstable in traction and easy to break in the CPP film blow molding processing process in the prior art.

Description

Blow molding processing method of CPP film

Technical Field

The invention relates to the field of high polymer materials, in particular to a blow molding processing method of a CPP film.

Background

The CPP is a polypropylene film produced by a tape casting extrusion molding process in the plastic industry, and the film is widely applied to various packages of human life after being printed and made into bags.

In the prior art, when a casting molding method or a blow molding method is adopted for production and processing of a CPP film, because of the particularity of a PP material, a flat extrusion blow-down method is generally adopted for processing, when the method is adopted, the PP raw material is firstly melted and plasticized in an extruder, the melted raw material is extruded downwards to form a thin-wall pipe through a downward right-angle machine head of a blow molding machine, then the thin-wall pipe is blown by compressed air to form a thin-wall pipe, the thin-wall pipe is cooled and shaped through an air ring, the shaped thin-wall pipe is clamped and flattened through a herringbone plate to form a jointed thin film, and finally the thin film is drawn to a take-up roller through a drawing roller to be taken up to form a thin film product; however, the processing by the flat extrusion blow-down method is liable to have the following problems:

firstly, the film tube is hung on the plastic section of the film which is not formed by cooling, so that the unstable traction condition of the film tube is easy to occur in the process of flat extrusion and downward blowing of the film.

Second, the film tube is easily broken by flat extrusion blow down.

Disclosure of Invention

The invention provides a blow molding processing method of a CPP film, which aims to solve the problems that a film tube is unstable in traction and is easy to break in the process of CPP film blow molding processing in the prior art.

In order to achieve the above object, the present invention provides a CPP film blow molding method, comprising the steps of:

(1) extruding a thin-walled tube: adding a PP raw material into a machine barrel of an extruder, rotating, extruding, stirring and pushing the PP raw material by a screw, and finally extruding the PP raw material into a thin-walled tube by a right-angle head, wherein the compression ratio of the screw is 2.8-4.0, and the extrusion temperature of the right-angle head is 200-;

(2) and blowing the thin-wall tube into a thin-film tube: compressed air is introduced into the thin-wall pipe, and the thin-wall pipe is blown into a thin-film pipe by the compressed air, wherein the blow-up ratio is 1.2-2.0;

(3) cooling and shaping the film tube: cooling the film pipe by adopting a mode of air cooling and water cooling, wherein the water temperature is 20-25 ℃, and the distance between the top of the cooling water ring and the bottom of the right-angle handpiece is 220-250 mm;

(4) and clamping the film tube: the film tube is clamped flat by two rotating belt lines in an inverted V shape, and the V-shaped included angle of the inverted V shape is 40 degrees;

(5) drawing and winding the film tube: the clamped film tube enters a traction roller for traction, and the film tube pressed by the traction roller enters a winding device through a guide roller.

Compared with the prior art, the beneficial effects of the technical scheme are as follows:

first, when the film forming length is the same, the flat-blowing-down method is used by means of the film tube entering into the drawing roll under its own weight, whereas the flat-blowing-up method or the flat-blowing-down method is used by drawing the film tube through the drawing roll. The contrast can know, because of the extrusion moves down that the film pipe relies on self gravity to remove downwards when blowing the method, and the translation rate is fast, therefore the cooling time of film pipe is short, but does not influence the characteristic of film pipe in order to guarantee the quick cooling of film pipe, adopts first forced air cooling as the precooling, accelerates cooling rate through the water-cooling again, and the film produces the poor problem of film opening nature because of cooling in the twinkling of an eye when avoiding singly adopting the water-cooling.

The second, is the pivoted belt line that falls the V style of calligraphy through two and presss from both sides the tie to the film pipe, and the film pipe produces the static that the friction generated with the belt line for there is the adsorption affinity between film pipe and the belt line, and when the film pipe entered into the belt line of falling the V style of calligraphy, the film pipe was flat pastes on the belt line, and the condition that the fold appears in the film before having avoided the film pipe to get into the carry over pinch rolls.

Thirdly, the film tube and the belt line generate friction to generate adsorption force generated by static electricity, which is equivalent to providing a force for avoiding shaking for the suspended film tube, and the problem of unstable traction generated in the traction process of the film tube is relieved.

Fourthly, the film tube and the belt line generate friction to generate an adsorption force generated by static electricity, which is equivalent to an upward supporting force for the film tube, and the condition that the film tube is broken due to the stress of a film plastic section which is not cooled and formed is reduced.

Further, the belt line in the fourth step is provided with chemical fiber cloth.

Has the advantages that: the chemical fiber cloth can be conveniently bonded on the belt line, the replacement is simple, and in addition, the static electricity generated by friction of the chemical fiber cloth and the PP film pipe is large, so that the chemical fiber cloth is favorable for providing stronger adsorption force.

Furthermore, the belt line is connected to a belt pulley, and the belt pulley is in transmission connection with the traction roller through a belt.

Has the advantages that: the traction roller drives the belt line to rotate, so that on one hand, the power of the traction roller can be further utilized, and the utilization rate of energy is increased; on the other hand, under the driving of the traction roller, the moving directions of the belt line and the film tube are just opposite, so that the relative movement between the film tube and the belt line is accelerated, and the generation of static electricity is favorably enhanced.

And furthermore, the fifth step also comprises the static removing treatment of the thin film tube, a spray barrel for removing static is arranged above the traction roller, antistatic liquid is filled in the spray barrel, and a liquid outlet hole is formed in the bottom of the spray barrel.

Has the advantages that: when the film tube is drawn by the drawing roller, the antistatic liquid in the spraying barrel flows out from the liquid outlet hole, and the antistatic liquid is neutralized by charges which generate static electricity by friction with chemical fiber cloth, so that the phenomenon that the static electricity of the film tube adsorbs dust in the air too much is avoided.

Furthermore, a sliding plate is connected in the spraying barrel in a sliding mode, a sliding rod is connected to the upper portion of the sliding plate, the antistatic liquid is located below the sliding plate, and two rubber blocks are filled in the liquid outlet hole.

Has the advantages that: the slide bar, the slide plate and the spray barrel form a piston, and the existence of the rubber blocks enables the piston to be sprayed out through the gap between the rubber blocks when the cavity inside the spray barrel is compressed, so that the use amount of the antistatic liquid is saved.

Furthermore, the belt pulley is eccentrically provided with a compression leg, the top of the sliding rod is fixedly connected with a pressing plate, the pressing plate can be abutted against the compression leg, the sliding rod is sleeved with an elastic part, one end of the elastic part is fixedly connected with the top of the inner cavity of the spraying barrel, and the other end of the elastic part is fixedly connected with the upper part of the sliding plate.

Has the advantages that: the belt pulley rotates to drive the pressure column to continuously press the pressure plate, and the pressure plate is recovered under the elastic action of the elastic element when being pressed once under the action of the elastic element, so that the state that the sliding rod moves up and down in a reciprocating manner is achieved, and the antistatic liquid is regularly sprayed onto the traction roller.

And furthermore, a cleaning roller is arranged beside the traction roller in the fifth step and is abutted against the traction roller.

Has the advantages that: the cleaning roller plays a cleaning role in the traction roller, after the antistatic liquid is sprayed onto the traction roller, the antistatic liquid flows onto the cleaning roller under the action of gravity to soften impurities on the traction roller, and meanwhile, the softened impurities are scraped off by the cleaning roller.

Drawings

FIG. 1 is a schematic diagram of a method for processing a CPP film by blow molding according to an embodiment of the present invention;

fig. 2 is an enlarged schematic view of a portion a in fig. 1.

Detailed Description

The following is further detailed by way of specific embodiments:

reference numerals in the drawings of the specification include: the device comprises a frame 1, an extruder 2, a right-angle head 21, an air-cooling water-cooling device 3, a cooling air ring 31, a cooling water ring 32, a top belt line 4, a traction roller 5, a driven rubber roller 51, a driving chromium-plated steel roller 52, a spray barrel 6, a sliding plate 7, a sliding rod 8, a rubber block 9, a compression column 10, a pressing plate 11, a spring 12, a cleaning roller 13, a guide roller 14, a winding device 15 and a film tube 16.

The embodiment is basically as shown in fig. 1 and fig. 2:

a blow molding processing method of a CPP film, the production processing method needs to use a blow molding processing mechanism of the CPP film, the blow molding processing mechanism of the CPP film comprises a frame 1 and an extruder 2, the extruder 2 is provided with a right-angle head 21, an air-cooled water cooling device 3 is arranged below the right-angle head 21, and the air-cooled water cooling device 3 comprises a cooling air ring 31 and a cooling water ring 32; two belt lines 4 in an inverted V shape are symmetrically arranged below the air cooling and water cooling device 3 along the central axis of the right-angle machine head 21, a traction roller 5 is arranged below each belt line 4, and each traction roller 5 comprises a passive rubber roller 51 and an active chromium-plated steel roller 52; the passive rubber roller 51 is positioned on the right side of the central axis of the right-angle machine head 21, and the active chromium-plated steel roller 52 is positioned on the left side of the central axis of the right-angle machine head 21; the belt line 4 is connected with a belt pulley, the belt pulley positioned on the left side of the central axis of the right-angle machine head 21 is in transmission connection with the driving chromium-plated steel roller 52 through a crossed belt, and the belt pulley positioned on the right side of the central axis of the right-angle machine head 21 is in transmission connection with the driven rubber roller 51 through the crossed belt; the belt line 4 is adhered with chemical fiber cloth.

A spray barrel 6 for removing static electricity is arranged above the active chromium plating steel roller 52, a sliding plate 7 is connected in the spray barrel 6 in a sliding manner, the upper part of the sliding plate 7 is connected with a sliding rod 8, an external coating type antistatic liquid is filled in the spray barrel 6 below the sliding plate 7, a liquid outlet hole is formed in the bottom of the spray barrel 6, and two rubber blocks 9 are plugged in the liquid outlet hole; a pressing column 10 is eccentrically arranged on the belt pulley on the right side of the central axis of the right-angle machine head 21, the top of the sliding rod 8 is fixedly connected with a pressing plate 11, the pressing plate 11 can be abutted against the pressing column 10, the sliding rod 8 is sleeved with a spring 12, the upper end of the spring 12 is fixedly connected with the top of an inner cavity of the spraying barrel 6, and the lower end of the spring 12 is fixedly connected with the upper part of the sliding plate 7; a cleaning roller 13 is arranged on the left side of the active chromium-plated steel roller 52, and the cleaning roller 13 abuts against the active chromium-plated steel roller 52; the extruder 2, the belt line 4, the traction roller 5, the cleaning roller 13, the guide roller 14 and the winding device 15 are all arranged on the frame 1.

The production processing method comprises the following steps:

(1) extruding a thin-walled tube: adding a PP raw material into a machine barrel of an extruder 2, rotating, extruding, stirring and pushing the PP raw material by a screw, and finally extruding the PP raw material into a thin-walled tube by a right-angle head 21, wherein the compression ratio of the screw is 3.0, and the extrusion temperature of the right-angle head 21 is 210 ℃;

(2) and the thin-wall tube is blown into a thin-film tube 16: compressed air is introduced into the thin-wall pipe, and the thin-wall pipe is blown into a thin-film pipe 16 by the compressed air, wherein the blow-up ratio is 1.5; the thin-wall tube is blown up to form a thin-film tube 16 according to the blowing-up ratio of 1.5 times under the action of compressed air;

(3) cooling and shaping the film tube 16: cooling the film tube 16 by adopting a mode of firstly air cooling and then water cooling, wherein the water temperature is 25 ℃, and the distance between the top of the cooling water ring 32 and the bottom of the right-angle handpiece 21 is 250 mm; the film tube 16 extends downwards under the self gravity, the film tube 16 is cooled by a cooling air ring 31, then cooled by a cooling water ring 32 at 25 ℃, and shaped by cooling the film tube 16 twice to prepare for entering the traction roller 5; because the film tube 16 moves downwards by means of self gravity during the flat extrusion blow-down method, the moving speed is high, so that the cooling time of the film tube 16 is short, in order to ensure the quick cooling of the film tube 16 and not to influence the characteristics of the film tube 16, air cooling is firstly adopted as precooling, and then water cooling is carried out to accelerate the cooling speed, thereby avoiding the problem that the film has poor film openness due to instant cooling when water cooling is singly adopted.

(4) And the thin film tube 16 is clamped flat: the thin film tube 16 is clamped flat by two rotating belt lines 4 in an inverted V shape, and the V-shaped included angle of the inverted V shape is 40 degrees; the film tube 16 moves downwards on the belt line 4 and generates static electricity by friction with the belt line 4, and the film is flattened before entering the traction roller 5 by the adsorption force generated by the static electricity; on the other hand, the adsorption force is equivalent to providing a force for avoiding the suspended thin film tube 16 from shaking, and the problem of unstable traction generated in the traction process of the thin film tube 16 is solved; in addition, the adsorption force is equivalent to an upward supporting force for the film tube 16, and the occurrence of film fracture caused by stress on the film plastic section of the film tube 16 which is not formed by cooling is reduced.

After the traction roller 5 rotates, the air bubbles on the film tube 16 are extruded out, and the film is simultaneously dragged; in addition, the traction roller 5 drives the belt line 4 to rotate, the moving directions of the belt line 4 and the film tube 16 are just opposite, the relative movement between the film tube 16 and the belt line 4 is accelerated, and the generation of static electricity is enhanced.

(5) Pulling and winding the film tube 16: the clamped flat film tube 16 enters a space between a passive rubber roller 51 and an active chromium plating steel roller 52 for traction, when the traction roller 5 pulls the film tube 16, the traction roller 5 rotates to drive a belt pulley of a belt line 4 to rotate, an eccentric pressing column 10 on the belt pulley continuously presses a pressing plate 11, the pressing plate 11 recovers under the action of elastic force every time the pressing plate is pressed once under the action of the elastic force of a spring 12, so that a sliding rod 8 is in a state of reciprocating up and down, the sliding block is regularly forced to spray an external coating type antistatic liquid in a spraying barrel 6 to the active chromium plating steel roller 52, the external coating type antistatic liquid is adhered to the film when the active chromium plating steel roller 52 rotates, the static on the film is eliminated, and the external coating type antistatic liquid is easy to volatilize from the film because the external coating type antistatic liquid contains alcohol components, and the subsequent rolling of the film is not influenced; the film tube 16 is thus destaticized by the overcoating type antistatic liquid ejected from the spray tub 6, and finally the film tube 16 pressed by the drawing roll 5 is introduced into the take-up device 15 through the guide roll 14.

In the process of rotating the belt line 4, the external coating type antistatic liquid is sprayed on the active chromium-plated steel roller 52 and then flows onto the cleaning roller 13 under the action of gravity, so that impurities on the active chromium-plated steel roller 52 are softened, and meanwhile, the softened impurities are scraped off by the cleaning roller 13.

The foregoing is merely an example of the present invention and well-known features and common sense in the art are not described in any greater detail herein. It should be noted that variations and modifications can be made by those skilled in the art without departing from the invention. These should also be construed as the scope of the present invention, and they should not be construed as affecting the effectiveness of the practice of the present invention or the applicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.

Claims

1. A blow molding processing method of a CPP film is characterized in that: the method comprises the following steps:

(4) and clamping the film tube: the film tube is clamped flat by two rotating belt lines in an inverted V shape, the V-shaped included angle of the inverted V shape is 40 degrees, chemical fiber cloth is arranged on the belt lines, the belt lines are connected to the belt pulleys, and the belt pulleys are in transmission connection with the traction rollers through belts;

(5) drawing and winding the film tube: the clamped film tube enters a traction roller for traction, and the film tube pressed by the traction roller enters a winding device through a guide roller;

the device also comprises a static removing treatment for the thin film tube, wherein a spray barrel for removing static is arranged above the traction roller, an antistatic liquid is filled in the spray barrel, and a liquid outlet hole is formed in the bottom of the spray barrel; a sliding plate is connected in the spraying barrel in a sliding manner, the upper part of the sliding plate is connected with a sliding rod, the antistatic liquid is positioned below the sliding plate, and two rubber blocks are plugged in the liquid outlet hole;

the eccentric compression leg that is equipped with on the belt pulley, slide bar top fixedly connected with clamp plate, the clamp plate can offset with the compression leg, and the cover has the elastic component on the slide bar, and the inner chamber top of bucket is spouted to elastic component one end fixed connection, and elastic component other end fixed connection slide upper portion.

2. The method for blow molding a CPP film according to claim 1, wherein: and (5) arranging a cleaning roller beside the traction roller, wherein the cleaning roller is abutted against the traction roller.