JPS6021651B2 - Manufacturing method of matte film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a matte film, and more particularly, to a method for producing a matte film made of a fluoropolymer that has excellent weather resistance, antifouling properties, etc. .

Fluoropolymer films take advantage of their excellent heat resistance, chemical resistance, electrical properties, non-adhesiveness, and even stiffness resistance, and are used as electrical insulation materials, anti-corrosion materials, mold release materials, etc. has a wide range of uses as film-resistant materials and the like.

Therefore, when used as a weatherproof covering material for road soundproof walls, road signboards, and high-quality plywood, it is preferable to reduce the light reflectance of the matte surface from the viewpoint of fenders or aesthetics. It is recommended that a film be used. However, common methods for producing matte plastic films include embossing a smooth film with a satin-treated hot roll, or embossing the surface of a smooth film using chemicals or spraying solid particles. Methods have been proposed in which a solution or dispersion of the plastic is cast onto a drum or endless belt having a matte surface to obtain a matte cast film. However, in the method of obtaining a matte film by embossing a smooth film or roughening it by chemical or physical means, in addition to the smooth film manufacturing equipment, special In addition, in the casting method, the film forming equipment itself becomes complicated, which is not only disadvantageous in industrial implementation, but also requires the cutting of the film in the matting process. There has been a drawback in that it is difficult to produce a thin matte film of, for example, 20 fm or less, due to the occurrence of wrinkles or the difficulty in peeling it off from the cast film. 25 The present inventors aimed to provide a means for solving the above-mentioned problems. As a result of extensive research, the inventors of the present invention have found that a specific amount of fluorine-based rubber-like elastic material coexists with a melt-moldable fluorine-containing polymer. By melt extrusion molding to a specific thickness, it is possible to directly produce a uniformly matte film using an ordinary extrusion molding machine, and it is also possible to produce a matte film as thin as, for example, 10 mm. We discovered an unexpected fact.

Thus, the present invention has been completed based on the above findings, and the fluorine-based rubber-like elastic material is used in an amount of 5 to 2 parts by weight based on the weight of the melt-formable fluoropolymer 10. The present invention provides a novel method for producing a matte film characterized by melt extrusion molding to a thickness of 50 mm or less in the presence of a matte film.

Examples of the melt-moldable fluoropolymer in the present invention include ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, tetrafluoroethylene-hexafluoroprobene copolymer, Examples include tetrafluoroethylene-perfluorovinyl ether copolymers, vinyldene fluoride polymers, and vinyl fluoride polymers.

Such polymers may have a volume flow rate of 10 as defined below.
~300 skin 3/sec, preferably 25 to 160 side 3/sec may be employed. As used herein, the term "volume flow rate" is defined as follows.

That is, using a Koka type flow tester, the nozzle diameter 1 fence, land 2
1 g of sample is melt-extruded from the rib nozzle 3, and the value expressed by the volume of the molten sample extruded per unit time is:
Defined as "volume flow rate", its units are side 3/sec. Here, the predetermined temperature is a temperature within the temperature range 3 (temperature range between the flow start temperature and thermal decomposition start temperature) in which the specific fluoropolymer can be melt-molded and close to the flow start temperature. Ru. Suitable fluoropolymers in the present invention include ethylene-tetrafluoroethylene copolymer 4 (hereinafter sometimes abbreviated as ETFE) and ethylene-tetrafluoroethylene copolymer (4) and ethylene-tetrafluoroethylene copolymer (hereinafter sometimes abbreviated as ETFE)
Hereinafter, it may be abbreviated as ECTFE).

That is, the molar ratio of tetrafluoroethylene (or chlorotrifluoroethylene)/ethylene is 40/60 to 7.
The degree of saturation is 0/3, especially about 45/55 to 60/40, and the capacity flow rate is 10 to 30 m3/sec, especially 25 to 16 m/s.
Particularly suitable is one with a wind velocity of about 0 wind 3/sec. Such suitable ETFE has a flow start temperature of about 260 to 300°C and a thermal decomposition start temperature of about 320 to 390°C. In addition, suitable ECTFE has a flow initiation temperature of 0 to 26 pi
, the thermal decomposition starting temperature is about 300 to 100 oz. Therefore, in the case of ETFE, the predetermined 0 temperature in the measurement of the volume flow rate and the temperature range adopted during the melt molding process are 2.
In the case of ECTFE, the temperature is selected from the range of 60 to 360°C and 220 to 50°C. Such suitable ETFE or ECTF
E is ethylene and tetrafluoroethylene or chlorotrifluorochloroethylene, as well as small amounts of comonomers (propylene, isobutylene, vinyl fluoride, vinylidene fluoride, hexafluoroproben, acrylic acid and alkyl esters, vinyl acetate, (perfluoroalkyl vinyl ether, hexafluoroisobutyrelin, perfluoroalkyl ethylene, etc.) or a modifier. In the present invention, the fluorine-based rubber-like elastic material may be conventionally known or well-known materials, without particular limitation.
A wide variety of examples may be given.

For example, tetrafluoroethylene-propylene copolymer, vinylidene fluoride-hexafluoroprobene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, vinylidene fluoride-bentafluoroprobene copolymer. combination, perfluoroacrylate elastomer, fluorine-containing siloxane elastomer, tetrafluoroethylene-vinylidene fluoride-propylene copolymer,
Tetrafluoroethylene-ethylene-isobutylene copolymer, ethylene-hexafluoroprobene copolymer, tetrafluoroethylene-butene-1 copolymer, tetrafluoroethylene-ethyl vinyl Examples include tetra-based copolymers, fluorine-containing phosphonitrile-based elastomers, and tetrafluoroethylene-fluorovinyl ether-based copolymers. The fluorine-based rubber-like elastic material used in the present invention is usually one having a number average molecular weight of 30,000 or more, preferably about 50,000 to 400,000, particularly one having a high molecular weight of about 10 to 25. Adopted.

The high molecular weight fluorine-based rubber-like elastomer suitable for the present invention consists of addition polymers such as tetrafluoroethylene-propylene-based copolymers and vinylidene fluoride-hexafluoroprobene-based copolymers. Such a suitable high molecular weight fluorine-based rubber-like elastic body is not particularly limited, and a wide range of examples may be used. For example, bulk polymerization,
Products manufactured by various polymerization methods such as suspension polymerization, emulsion polymerization, and solution polymerization, catalytic polymerization methods using polymerization initiators,
Various examples include those produced by ionizing radiation polymerization method, redox polymerization J method, and the like. Therefore, the preferred tetrafluoroethylene-propylene copolymer elastomer contains, in addition to the main components of tetrafluoroethylene and propylene, components that can be copolymerized with Z, such as ethylene, isobutylene, and acrylic. Acid and its alkyl ester, methacrylic acid and its alkyl ester, vinyl fluoride, vinylidene fluoride, hexafluoroproben, chloroethyl pinylether, chlorotrifluoroethylene, /fluoroalkyl vinyl ether, etc. It may also be a tetrafluoroethylene-propylene copolymer containing an appropriate amount of.

Therefore, the molar ratio of tetrafluoroethylene and propylene constituting the copolymer, the molar ratio of 2 to other components added as necessary, the molecular weight of the copolymer, etc., are determined according to the target material to be treated. It can be arbitrarily selected depending on the usage, heat and chemical resistance elastomer properties, ease of acquisition, etc. For example, in the present invention, the molar ratio of tetrafluoroethylene/propylene is 99/1 to 10/90, preferably 95/5 to 30/90, considering the excellent heat resistance that is a feature of the present copolymer. 70, especially tetrafluoroethylene-propylene copolymers having a ratio of 90/10 to 45/55. The content of the above-mentioned components other than the main components of tetrafluoroethylene and propylene is 0 to 50 mol%, preferably 0.
．． About 5 to 40 mol% may be employed. Further, it is desirable to use a copolymer having a molecular weight of about 50,000 or more, and a copolymer having a moderately high molecular weight can provide advantageous applicability. For example, a tetrafluoroethylene-propylene copolymer having a molecular weight of 70,000 or more, preferably about 100,000 to 250,000 can be used. or,
A suitable vinylidene fluoride, hexafluoroproben-based copolymer elastomer also includes, in addition to the main components of vinylidene fluoride and hexafluoroproben, components that can be copolymerized with these, such as tetrafluoroethylene,
Perfluorovinyl ether, acrylic acid and its alkyl ester, methacrylic acid and its alkyl ester, etc. may be appropriately contained therein. The molar ratio of vinylidene fluoride/hexafluoroprobene is 9
5/5 to 40/60, preferably 90/10 to 60/4
Vinylidene fluoride/hexafluoroprobene copolymers such as 0 are widely used, and tetrafluoroethylene, /fluorovinyl ether, etc. are copolymerized in an amount of 0 to 40 mol%, preferably 10 to 30 mol%. It's okay if it's done. The molecular weight of such a copolymer is also 5 as mentioned above.
It is preferable that the molecular weight is as high as possible, for example, 70,000 or more, particularly about 100,000 to 250,000. In the present invention, it is important that the proportion of the fluorine-based rubber-like elastic material as described above is 5 to 2 parts by weight, preferably 8 to 15 parts by weight, based on 100 parts by weight of the fluoropolymer. .

If the proportion of fluorine-based rubber-like elastic material is too small, the matting effect will not be observed, and if it is too large,
Various drawbacks arise due to a decrease in film formability and an increase in the rubbery properties of the produced film, such as a decrease in workability when used as a covering material due to a decrease in so-called stiffness. In the present invention, it is preferable that the fluoropolymer and the fluorine-based rubber-like elastomer are mixed in the above-mentioned ratio and then supplied to the extrusion molding machine.

Mixing can be carried out by various methods, but the fluorine-based rubber-like elastic material is cryogenically ground into powder particles with a diameter of about 0.5 to 3 willows, and this is mixed into pellets or granules of the fluoropolymer. A method of mixing using beads and a V-type blender can be preferably adopted. In the present invention, it is important to form a mixture of a fluoropolymer and a fluoropolymer into a film with a thickness of 50 mm or less, preferably 20 mm or less, by melt extrusion molding.

When producing a film without extrusion molding, for example, the film may be obtained by forming a coating film of the above mixture on various substrates by a dispersion method or a powder spraying method, and then removing the base material. It does not result in a uniform matte film. Furthermore, if the thickness of the extruded product is too large, the matting effect will be reduced, which is not preferable. Therefore, the structure of the molding machine and the molding conditions when performing extrusion molding may be essentially the same as those for producing a smooth film, but the tin content of the smooth film may also lower the die temperature to some extent. It is also possible to increase the matte effect by setting it on the eyes. In the present invention, the reason why the addition of the fluorine-based rubber-like elastomer produces a matting effect is not necessarily clear, but it may be due to the occurrence of melt fracture phenomenon due to a decrease in the critical breaking stress of the mixed melt, or the occurrence of melt fracture during solidification. It is understood to be related to the microphase separation phenomenon of both components.

Note that this explanation does not limit the present invention in any way, but is provided to make it easier to understand the characteristics of the present invention. The matte film obtained by the present invention contains a small amount of fluorine-based rubber-like elastic material in addition to the fluorine-based polymer;
Compared to fluoropolymer alone, weather resistance, heat resistance,
Almost no deterioration in chemical resistance, antifouling properties, electrical properties, etc. is observed. Furthermore, according to the method of the present invention, it is possible to produce thin films of about 10 cm, which were difficult to produce in the conventional method due to the difficulty of cutting the film during the matting process, the occurrence of wrinkles, or the difficulty of peeling it off from the cast base material. It is also possible to produce matte films, and the films thus obtained are particularly useful as weatherproof coatings for road noise barriers, road sign boards or decorative plywood. Next, the present invention will be explained in more detail with reference to Examples, but it goes without saying that the present invention is not limited by such explanations.

In addition, in the following Examples and Comparative Examples, 45 degree specular gloss (hereinafter referred to as Gs(45o)) is used as a guide for the matte effect.
A test piece prepared by attaching a part of the film to be measured to black paper using a thin double-sided adhesive tape was measured in accordance with JIS Z8741-196Z method 3.

Here, it is shown that the matting effect is large when the value of Gs (45o) is 4.00, and from the correspondence with visual perception, a practically sufficient matting effect is achieved when the value is 30% or less, especially 20% or less. It is determined that the Example 1 An ethylene-tetrafluoroethylene copolymer containing 53 mol % of units based on tetrafluoroethylene (melting point 266oo, thermal decomposition initiation temperature 352°C, volumetric flow rate at 300 qo 9 3/sec) The beads and a low-temperature pulverized product (particle size approximately 2 sides) of a tetrafluoroethylene-propylene copolymer (thermal decomposition onset temperature 380 oo, molecular weight 160,000) containing 56 mol% of units based on tetrafluoroethylene are weighed. Mix in a V-type blender at a ratio of 100:10, and use a 4-meter extruder to form a mixture at cylinder temperature [Zone 1] 270°C, [Zone 2] 2
85°C, [Zone 3] 295qC, crosshead temperature 300oo, die tip temperature 315°C, lip gap 0.
2 ribs, screw rotation speed 18pm, take-up speed 5.2h/
A film with a thickness of 12 mm was formed under the following conditions.

The film thus obtained is uniformly matte;
Its Gs(45o) was 12%. On the contrary,
When the blending weight ratio of the ethylene-tetrafluoroethylene copolymer and the tetrafluoroethylene-propylene copolymer is 100:2, the G of the resulting film is
s(450) was as high as 94%, which was not much different from that of an ethylene-tetrafluoroethylene copolymer sole film (108%) molded on the same machine under the same conditions.

In addition, when the above blending weight ratio is 100:33, 1
It was difficult to form a uniform film with a thickness of 5 m. Examples 2 to 4 and Comparative Examples 1 to 2 Using the same machine as Example 1, various matte films of fluoropolymer were obtained.

Claims (1)

[Claims] 1. When producing a melt-moldable matte film of a fluorine-based polymer, 5 to 5 parts by weight per 100 parts by weight of the polymer.
A method for producing a matte film, which comprises melt extrusion molding to a thickness of 50 μm or less in the coexistence of a fluorine-based rubber-like elastic material in an amount equivalent to 20 parts by weight. 2. Claim 1, wherein the melt-moldable fluorine-based polymer is an ethylene-tetrafluoroethylene-based copolymer.
The method described in section. 3 The fluorine-based rubber-like elastic body is tetrafluoroethylene.
The method according to claim 1, which is a propylene copolymer. 4. The method according to claim 1, wherein the matte film has a thickness of 20 μm or less.