JP2003266519A - Method for manufacturing resin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polyester film, which is excellent in mechanical characteristics; is excellent in design properties in which whitening is not generated by using a film alone or laminating it with a metal sheet even when it exhibits a high degree of crystallization and it is heat-treated to the vicinity of the melting point or at the melting point or higher of the film; and is preferably hardly wounded after lamination to be used for metal lamination and for molding processing. <P>SOLUTION: The method manufactures a resin film by mixing and extruding two kinds of resin raw materials of different constitutions. A raw material A and a raw material B are respectively fed into separate extruders and are melted therein, and then they are fed into a mixing apparatus under molten conditions and are mixed and extruded. <P>COPYRIGHT: (C)2003,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a film suitable for various food packaging, general industrial use, optical use, electrical material use, molding process, etc. by mixing and extruding resin raw materials of two different types, The present invention relates to a method for producing a film useful as a constituent material of a film-laminated metal plate.

[0001]

2. Description of the Related Art A metal can, which is a form of a food and drink packaging container, can be stored for a long period of time because of its excellent mechanical strength, and the contents can be filled at a high temperature and then sealed as it is. Since it can be easily sterilized such as retort treatment, it is highly reliable in terms of safety and hygiene as a packaging container, and it is possible to store the contents in a heated state and to separate the collected can bodies after use relatively easily. Due to its many advantages, various contents have been filled and used in large amounts in recent years.

The inner and outer surfaces of metal cans for food and drink are conventionally made of a thermosetting resin in order to maintain the flavor of the contents and prevent corrosion of the metal cans, or to improve the outer appearance of the cans and to protect the printing surface. The paint, which is the main component, has been applied and used on metal cans. However, since such a metal can uses a large amount of solvent at the time of manufacturing, it may cause environmental impact due to solvent removal during manufacturing, hygiene problems due to residual solvent in the coating film, and poor reaction during heat curing. There are problems such as deterioration of flavor due to the remaining oligomer.

In order to overcome these problems, a method of laminating a plastic film on a metal has been proposed. As a metal plate obtained by laminating a polyester resin film on a metal plate, a so-called 3-piece can (hereinafter referred to as 3P can
Two-piece cans (hereinafter abbreviated as cans) and two-piece cans have been proposed. From the perspective of making cans seamless, the spread of 2P cans is desired.

As a general method for producing a 2P can, a method in which a metal plate laminated with a plastic film is punched by a can making machine and drawn and ironed to form a seamless can is generally used. In this can-making process, the film is required to follow the extension of the metal plate while being subjected to the squeezing and ironing shear.

In response to these required properties, a polyethylene terephthalate (PET) type polyester resin having a specific intrinsic viscosity and a polybutylene terephthalate (PBT) type polyester resin having a specific intrinsic viscosity are blended to obtain a can-making property. Excellent films have been proposed (see, for example, Patent Documents 1, 2, and 3).

By using a film made of two kinds of polyester, both the film follows the deformation of the metal during can forming and the flavor of the can contents. For that purpose, it is necessary to have appropriate crystallinity. For that purpose, it is necessary to prevent the copolymerization of different polyesters by the transesterification reaction. Therefore, for example, measures have been taken to reduce the amount of heat applied to the film during the melting time of the resin and the subsequent stretching and heat treatment steps. However, in any of the case where the film is attached to a metal and the case where the film is formed as it is, when treated near the melting point of the film or above the melting point, the film is whitened with cooling, which is inferior in designability, which is preferable. There wasn't. Further, there is a problem that the film on the metal plate is easily scratched due to the decrease in the viscosity of the film.

The cause is expected as follows. PET
In order to mix resins with different melting points like PBT and
It is necessary to melt at a temperature higher than the melting point of PET having a high melting point (about 255 ° C). Therefore, PBT with a low melting point (about 225
(° C), the temperature is higher than the optimum extrusion temperature, so that deterioration of the resin and deterioration of the viscosity cause deterioration of the quality. Also, PET
It seems that the crystallization rate of PBT and PBT changes depending on the mixed state of both, but if the mixing is insufficient or insufficient, the crystallization rate will decrease, and it will cause whitening.

[0008]

[Patent Document 1] Japanese Patent No. 2882985

[0009]

[Patent Document 2] Japanese Patent No. 3020731

[0010]

[Patent Document 3] Japanese Patent Laid-Open No. 10-195210

[0011]

[Patent Document 4] Japanese Patent Laid-Open No. 10-110046

[0012]

In the present invention, 2
It relates to a method of forming a film by mixing and extruding resin raw materials of different types of composition, preferably having excellent mechanical properties, even if it has a high degree of crystallinity, the film is laminated alone or with a metal plate, The present invention relates to a method for producing a polyester film having excellent design properties that does not whiten even when heat-treated near or above the melting point of the film, and is preferably scratch-resistant even after lamination, preferably for metal laminating and molding.

[0013]

Means for Solving the Problems The present invention is a method of mixing and extruding two kinds of resin raw materials having different constitutions to form a film, in which the raw material A and the raw material B are put into separate extruders and melted. The present invention relates to a method for producing a resin film obtained by supplying the mixture in a molten state to one mixing device, mixing and extruding the mixture.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The resin used in the present invention is
It is not limited, and examples thereof include polypropylene, polyethylene, polystyrene, polymethylpentene, cyclic olefin resin, acrylic resin, polycarbonate, polyphenylene sulfide, vinyl resin, polylactic acid, etc., preferably nylon resin, more preferably polyethylene terephthalate. Polyester resins such as polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and polytrimethylene naphthalate. Also, a copolyester can be used. Acid components include terephthalic acid, isophthalic acid, naphthalene acid, sebacic acid, adipic acid and dimer acid, and glycol components include ethylene glycol, trimethylene glycol (propylene glycol), butanediol, diethylene glycol, cyclohexanone dimethanol, cyclohexane. Dimethanol, neopentyl glycol, etc. are used. Also,
Random polymerization resin, block polymerization resin, etc. can be used according to the design.

The polyester used in the present invention is a product obtained by melt polycondensation reaction or subsequent solid-phase polymerization. The reduced viscosity is preferably 0.55 to 2.00, more preferably 0.58 to 1.50. If the reduced viscosity is less than 0.55, the strength of the film is insufficient, and if it exceeds 2.00, film formation is difficult.

In the present invention, the method for producing the film used is a method for producing a film by mixing and extruding two kinds of resin raw materials having different constitutions, and the raw material A and the raw material B are put into separate extruders and melted. After that, it is obtained by being fed to one mixing device in the molten state, mixed, and extruded. When a film is made using two different types of resins, preferably two different types of polyester, it is necessary to control the mixed state of the two. Preferably, in the case of a polyester film for metal laminating, it has a can-forming property and a flavor property,
Moreover, it is necessary to prevent whitening of the film after molding. For that purpose, in order to control the crystallization rate and the degree of crystallization, it is necessary to suppress the transesterification reaction between the polyester A and the polyester B so that they are not copolymerized.

When a transesterification reaction is generated between the polyester resins (A) and (B), a copolymer of the polyester resin (A) and the polyester resin (B) is generated, and the polyester resin (A) The ethylene terephthalate structure, which is the main component structure, is randomized and its characteristic rigidity is impaired, while the butylene terephthalate structure, trimethylene terephthalate structure or 2,6 naphthalate structure, which is the main component structure of the polyester resin (B), is random. And its high crystallinity, which is a characteristic of the above, is deteriorated. Also, when considering high level processability and designability,
Suppression of transesterification is not enough. The reason is expected to be the following phenomenon. Even when the transesterification reaction is suppressed, when polyethylene terephthalate and polyester B are more finely dispersed and compatible with each other, crystallization becomes slower and whitening is likely to occur. For that purpose, it seems preferable to reduce the dispersion and / or compatibility of polyethylene terephthalate and polyester B, that is, to make a coarse mixture.

Therefore, in order to satisfy the above points, the following manufacturing method is preferably used in the present invention. As a manufacturing method, polyester A having a different melting point,
Since B can be melted at each appropriate temperature (melting point + 30 ° C or less), polyesters A and B are put into separate extruders, and the melted polyesters are mixed before being extruded from the die to form a die. It is a method of guiding, melting and extruding.

In the usual polyester film production, the materials constituting a single layer are charged into a single extruder,
It is melted and extruded to form a film. Even in the patents exemplified in the section of the prior art, the extruder uses a single extruder although two or more different materials are used. This is presumed to be the result of considering the stability and economical efficiency during the film formation by the conventional technique. Therefore, higher quality films seemed difficult. However, by adopting the method described later, while maintaining the stability of film formation,
It has been found that a film of improved quality is obtained.

The reason why this method is good in quality and productivity is as follows.
It is assumed to be as follows. For example, PET (melting point 255 ° C) and PBT (melting point 220 ° C) using only a single extruder with single or twin screw which is a commonly used method.
In the case of producing a blend film of (° C), the difference in melting point between the two is 30 ° C or more, and therefore when the both are blended from the resin chip stage, the temperature of the extruder needs to be set to the melting point of PET or higher. Also, it is usually set at 280 ℃ or higher in consideration of production stability. Since PBT has a decomposition rate higher than 260 ° C and further around 280 ° C, the molecular weight becomes small due to the heat of the extruder. As a result, the compatibility with PET is improved and the homogenization is further promoted, which facilitates copolymerization. For example, both polyesters do not copolymerize and have a crystallinity suggested to be nearly independent. However, the independence of the crystallinity at a higher level is not maintained, possibly because of mutual influences, and therefore the crystallization rate cannot be improved, resulting in prevention of whitening at a higher level. It is presumed that

Particularly when a slow compression type extruder is used, when an extruder having a large compression ratio is used, and when the L / D is large (estimated to be 35 or more), the apparent set temperature can be set low, but the extruder can be set. Probably because the amount of self-heating in the compression section (compression zone) of the resin becomes large and the temperature of the resin becomes higher than the set temperature, PTT, PBT, PH having a low melting point.
T seems to be easily decomposed.

Examples of the machine base for mixing the melted polyesters include a normal single-screw extruder, a twin-screw extruder, a dynamic mixer, a static mixer (manufactured by Noritake Company, etc.) and the like. Especially when mixing the melted resins separately, when using a normal single-screw or twin-screw extruder, in order not to mix the two so much that they are uniformly mixed and compatible with each other, one with a small compression ratio, the whole extruder screw and It is required that the compression section has a small L / D.

From the above point of view, in the present invention, it is preferable to independently melt each raw material and then mix the respective resins. Therefore, it is preferable to use two or more extruders in parallel, but in order to achieve the present application using a single extruder, the screw compression section (compression zone) in a single-screw extruder is a double flight type. That is a rapid compression type and has a small compression ratio (2.
It can be achieved by using the one of 0 or less). The UB series manufactured by Mitsubishi Heavy Industries can be used as an extruder with a double-flight type screw, but it is not achieved by all of them, and it seems that the above-mentioned conditions must be met. The reason is presumed to be as follows. The PBT that started to melt earlier due to the double flight in the compression part of the screw and the PET that remains solid at that time are separated in the first flight of the compression part, so PET and PB
It is speculated that this is effective because the contact time of T is shortened. However, since this method has a narrow allowable range of conditions, it is preferable to use two or more extruders in parallel.

Taking these into consideration, in the method of mixing and extruding two kinds of resin raw materials having different constitutions to form a film, the raw material A and the raw material B, preferably the polyester A and the polyester B, are respectively charged into different extruders. After being melted, it is necessary to supply it to a single mixing device in the molten state, mix it, extrude it, and preferably orient it at least uniaxially.

As the extruder for melting and extruding the raw materials A and B, an ordinary single-screw extruder or twin-screw extruder can be used.
Further, as a mixing device for supplying the resin supplied from each extruder in a molten state, a single-screw extruder, a twin-screw extruder, a dynamic mixer, a static mixer or the like can be used.

In the present invention, the raw materials A and B may be a single raw material or a mixture. Silicon dioxide, kaolin, clay, calcium carbonate, calcium terephthalate, aluminum oxide, titanium oxide, calcium phosphate, silicone particles, if necessary, stabilizer, colorant,
Additives such as antioxidants, defoamers, antistatic agents, etc. can be contained. Even in the case of a mixture, preferably, the main component of each raw material is 60% or more, more preferably 80% or more, and further preferably 90% or more is a single raw material. In the present invention, the difference between the melting points of raw materials A and B is preferably 15 ° C.
Or more, more preferably 20 ° C or more, further preferably 25 ° C
It is an effective manufacturing method when using the above.

For general packaging, antistatic property, gas barrier property,
For metal laminating, heat sealing, anti-fog, metal deposition,
Easy tearing, easy opening, bag making packaging, retort packaging, boil packaging, medicine packaging, easy adhesion, magnetic recording, capacitors, ink ribbon, transfer, adhesive labels, stamping foil, It can be used as a manufacturing method for gold and silver threads, tracing materials, mold release, shrink film, and the like.

[0028]

EXAMPLES The present invention will be specifically described below with reference to examples. still,
Each characteristic value of the polyester in the examples was measured as follows.

1. Reduced viscosity Reduced viscosity (ηsp / C) 0.125 g of a polymer was dissolved in 25 ml of phenol / tetrachloroethane = 6/4 (weight ratio) and measured at 25 ° C. using an Ubbelohde viscosity tube. The unit is dl / g.

2. Melting point (TmL, TmH) of film, crystallization temperature (Tc2) and full width at half maximum of crystallization peak Using DSC3100S manufactured by Rigaku Electric Co., put the film in a sample pan, cover the pan with nitrogen, Polyester resin (A) and polyester resin (B) measured from room temperature to 280 ° C. in a gas atmosphere at a heating rate of 20 ° C./min.
The temperature at the peak top of the melting peak of the origin is TmH and TmL, respectively. Also, when the sample that has reached 280 ° C is held for 1 minute as it is, then it is cooled to room temperature at a rate of 20 ° C / minute, and measured. The temperature at the peak top of the crystallization peak of was defined as Tc2, and the height h from the baseline of this peak was divided by the temperature width l at a height of 0.5 h to give 1 / h as the half-value width. (Lamination conditions) Lamination temperature 220 ℃ Linear pressure 10N / cm

3. Laminate the whitening film on an aluminum plate under the following conditions, and
Leave in gear oven for 1 minute at 0 ° C and 290 ° C (2 levels). Then, air cooled at 25 ° C. was applied to the film surface of the laminate at a wind speed of 20 m / min, and the cooled film was visually judged.・ ・ ・ No whitening before and after heat treatment ○ ・ ・ ・ ・ Practically none △ ・ ・ ・ ・ Whitening is observed × ・ ・ ・ ・ Whitening is remarkable

4. Hardness 3. Rubbing the film surface of the laminated plate treated with above with a sharpened point of the pencil lead. It is represented by the highest pencil hardness that was not scratched at that time.

5. Canning film 2. Laminated on an aluminum plate under the conditions
After processing at 0 ° C., the presence or absence of damage such as peeling, breakage, and cracks of the film after forming the can body was observed visually and with a fluorescent microscope (magnification: 80 times), and evaluated based on the following criteria. ◎ ・ ・ ・ ・ Out of 100 cans, 95 or more are not damaged. ○ ... ・ 80 to 94 out of 100 cans were not damaged. Δ: 70 to 79 out of 100 cans were not damaged. × ... 31 or more out of 100 cans have some damage in the present invention, Δ is preferable, ○ is more preferable, and ◎ is more preferable.
Is required.

Example 1 As the polyester resin A, silicon dioxide (D) was previously prepared (Fuji Silysia made Silysia 310).
Polyethylene terephthalate resin (reduced viscosity 0.75, catalyst germanium dioxide, melting point of resin 255 ° C.) added at the time of polymerization of 2000 ppm of 60 mmφ extruder (I) (L
/ D = 29 The compression ratio was 4.2) and the mixture was melted at 275 ° C. As the polyester resin B, polybutylene terephthalate resin (Toray 1200S, reduced viscosity 1.30, resin melting point 22
5 ° C) and organophosphorus compound (C) (ADEKA STAB PEP)
-45: 300 ppm of Asahi Denka Kogyo Co., Ltd. was charged into another 60 mmφ extruder (II) (L / D = 29 compression ratio 4.2) and melted at 240 ° C. After that, each raw material of I and II I / II =
90mm in the molten state so that it becomes 4/6 (weight ratio)
Lead to φ extruder (III) (L / D = 25 compression ratio 1.5) and put in
After mixing, melting and extruding from a T-die, an unstretched sheet having a thickness of 200 μm was obtained. At this time, the temperature of the cylinder part and the filter part (200 mesh) of the extruder III was 260 ° C., and the temperature from the screw tip part of the extruder to the T-die was 25 ° C.
The temperature of the resin discharged from the T-die was 257 ° C. The pressure of the resin immediately before entering the T-die was set to 8.8 MPa (90 kgf / cm ² ). This unstretched sheet is introduced into a roll stretching machine, stretched in the longitudinal direction at 70 ° C by 3.3 times, further stretched in the transverse direction at 95 ° C by 3.5 times, and then stretched in the tenter in the transverse direction. A film having a thickness of 17 μm was obtained by heat setting at 150 ° C. while relaxing by 3%. Table 1 for characteristic values
Shown in.

(Example 2) In Example 1, the raw material of the extruder II was used as the polyester resin B and the organic phosphorus compound (C).
(ADEKA STAB PEP-45: Asahi Denka Kogyo (manufactured) 300pp
A film was obtained in exactly the same manner except that polybutylene terephthalate resin (1200S manufactured by Toray, reduced viscosity 1.30) in which m and talc were pre-kneaded at 500 ppm and the heat setting was 220 ° C. The temperature of the resin discharged from the T-die is 2
It was 58 ° C.

(Example 3) In Example 1, the extruder II was used.
A film was obtained in exactly the same manner except that the compression ratio of I was 4.0. All the conditions such as temperature setting were the same as in Example 1 (however, heat setting was 220 ° C.), but the temperature of the resin discharged from the T-die was 263 ° C.

(Comparative Example 1) Polyesters A and B and an organophosphorus compound in Example 1 were introduced into an extruder III (L / D = 25, compression ratio 4.0) as pellets so that the composition ratio was the same, and the temperature conditions were adjusted. A film was obtained in the same manner as in Example 1 except that was extruded in the same manner as in Example 1. The temperature conditions were set the same as in Example 1, but the temperature of the resin discharged from the T-die was 265 ° C.

Example 4 A film was obtained in the same manner as in Example 1, except that polytrimethylene terephthalate (reduced viscosity 0.98, melting point of resin 232 ° C.) was used instead of polybutylene terephthalate. The temperature of the resin exiting the T-die was 260 ° C.

(Example 5) Extruder III in Example 1
Instead of static mixer (12 elements,
A film was obtained in the same manner except that the cylinder temperature was 258 ° C. The temperature of the resin discharged from the T-die is 25
Was 8 ° C

(Example 6) 6,6-nylon resin was placed in the extruder I and 6-nylon resin was placed in the extruder II, and the longitudinal stretching temperature was 60 ° C and the transverse stretching temperature was 80 ° C. Is 22
A film was obtained in the same manner as in Example 1 except that the temperature was 0 ° C.

Example 7 Instead of the PBT resin, polyhexamethylene terephthalate (PH having a reduced viscosity of 0.85) was used.
T) and the resin ratio from extruders I and II is 90: 1.
A film was obtained in the same manner as in Example 1 except that 0 (weight ratio) was used.

Example 8 Polyethylene-2,6-naphthalate (PEN) having a reduced viscosity of 0.88 was used in place of the PBT resin, and the resin ratio from the extruders I and II was 90:10 (weight). A film was obtained in the same manner as in Example 1 except that the ratio was used.

Comparative Examples 2 and 3 PET alone containing 0.1% by weight of silica or P containing 0.1% by weight of silica
A film was obtained in the same manner as in Comparative Example 4 except that only BT was used as the raw material.

(Example 9) A film having a thickness of 38 µm was obtained in the same manner as in Example 1 and then molded at 90 ° C using a mold to obtain a mobile phone having a depth of 5 mm x a width of 50 mm x a length of 50 mm. A liquid crystal surface cover was created. It was confirmed that it did not whiten and was good, and that it was also good for molding.

[0045]

[Table 1]

[0046]

In the present invention, the mechanical properties are excellent,
The present invention relates to a polyester film which has a high degree of crystallinity, is excellent in design and does not whiten even when heat-treated near or above the melting point of the film, which is adhered to the film alone or to a metal plate, and is not easily scratched. For general packaging, antistatic property, gas barrier property, for metal laminating, for heat sealing, anti-fog,
Metal deposition, easy tearing, easy opening, bag making packaging, retort packaging, boil packaging, medicine packaging, easy adhesion, magnetic recording, capacitors, ink ribbons, transfer, adhesive labels, stamping It is the most suitable manufacturing method for foil, gold and silver thread, tracing material, mold release, shrink film, etc.

[Brief description of drawings]

FIG. 1 How to determine the half-width of Tc2

[Meaning of sign]

1 Line measured by DSC 2 baseline Height h from the baseline of 3 peaks 4 Height from baseline 0.5 5 Temperature range 1 at a height of 0.5h from the baseline

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29L 9:00 B29L 9:00 (72) Inventor Shinji Fujita 2-1-1 Katata, Otsu, Shiga Prefecture Toyobo Achievement F-term in Research Institute Co., Ltd. (reference) 4F201 AG01 AH54 BA01 BC01 BC12 BC37 BD05 BK02 BK06 BK13 BK31 4F207 AA24 AG01 AG03 KA01 KA17 KF01 KK13 KW41 4F210 AA24 AA25 AB16 AB17 AG01 AG03 QC06 QG01 QG15 QG18

Claims (7)

[Claims] 1. A method for producing a film by mixing and extruding two or more kinds of resin raw materials having different constitutions, the raw material A
The raw material B and the raw material B are respectively charged into separate extruders, melted, and then supplied to one mixing device in a molten state, mixed,
Method for producing resin film obtained by extrusion 2. The manufacturing method according to claim 1, wherein the melting point difference between the raw material A and the raw material B is 15 ° C. or more. 3. The raw material A and the raw material B are 60 polyester resin.
% Or more is contained, The manufacturing method of the polyester film of Claim 1 or 2 characterized by the above-mentioned. 4. The method for producing a polyester film according to claim 3, wherein the raw material A and the raw material B are different polyester resins. 5. The manufacturing method according to claim 1, wherein the mixing device is selected from one of a single-screw extruder, a twin-screw extruder, a dynamic mixer, and a static mixer. 6. The method for producing a film according to claim 1, wherein the film is stretched in at least one axial direction. 7. The method for producing a film according to claim 1, wherein the film is for metal laminating or forming.