JP2830046B2 - Soft PVC sheet - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a flexible PVC sheet.

[Prior Art] For the purpose of improving the weather resistance and the antifouling property, a flexible PVC sheet which is protectively coated with a coating material having relatively excellent weather resistance such as an acrylic resin is often used.

Further, for the purpose of further improving the weather resistance, a protective coating with a coating material made of a fluororesin has been proposed (Japanese Patent Application Laid-Open No. 60-11043).

[Problems to be Solved by the Invention] Conventionally, a vinylidene fluoride-based laminated sheet, which is known as a soft PVC sheet having excellent weather resistance, has poor adhesion between a protective coat and a sheet and cannot be sufficiently used. Did not.

An object of the present invention is to solve the above-mentioned problems of the prior art, that is, to provide a flexible PVC sheet having excellent weather resistance and excellent adhesion of a protective coat.

[Means for Solving the Problems] The present invention relates to a fluorine-containing flexible vinyl sheet containing 30 to 70 mol% of a unit based on fluoroolefin comprising tetrafluoroethylene and / or chlorotrifluoroethylene and having a cross-linking site. Provided is a flexible PVC sheet formed by forming a coating film of a paint containing a copolymer (a) and an acrylic polymer (b) compatible with (a) as a main component.

Examples of the vinyl chloride resin as a base material of the flexible PVC sheet of the present invention include vinyl chloride homopolymer, vinyl chloride and vinyl acetate, ethylene, propylene, (meth) acrylate [acrylate and methacrylic acid] Esters are thus collectively referred to, as well as others. And at least 40% by weight, preferably at most 30% by weight, of a monomer such as a polymer, and a polymer compatible with these homopolymers or copolymers, for example, , An ethylene-vinyl acetate copolymer, a vinyl chloride-vinyl acetate copolymer and the like may be blended.

Further, an appropriate amount of a plasticizer is blended with the vinyl chloride resin and used as a softened vinyl chloride resin. The amount of the plasticizer is 30 to 7 parts per 100 parts by weight of the vinyl chloride resin.
A range of about 0 parts by weight is preferably employed. Examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, diisodecyl adipate, tricresyl phosphate, epoxidized soybean oil, and epoxidized linseed oil. Further, ordinary additives such as a lubricant, an antioxidant, an antistatic agent, a heat stabilizer, a colorant, and a flame retardant may be added to the vinyl chloride resin.

Further, a surfactant may be added to the vinyl chloride resin for the purpose of preventing fogging. As the surfactant, a nonionic surfactant is preferably employed.

Such soft PVC sheets are used for truck hood tents, flexible containers, eaves sheets for stores, signboards, table cloths, desk mats, marking films called paints to be pasted, and the like.

In the present invention, as a coating material for forming a film on the soft PVC sheet, "tetrafluoroethylene and / or
Or a fluorinated copolymer (a) containing a unit based on a fluoroolefin composed of chlorotrifluoroethylene in an amount of 30 to 70 mol% and having a crosslinking site [hereinafter, simply referred to as a fluorinated copolymer (a)] and ( An acrylic polymer (b) compatible with a) is mainly used.

Here, the fluorine-containing copolymer (a) has a fluorine content of 10 based on a “fluoroolefin composed of tetrafluoroethylene and / or chlorotrifluoroethylene” (hereinafter simply referred to as fluoroolefin) unit.
A solvent-soluble fluorine-containing copolymer having a content of not less than% by weight is preferably employed.

The fluorine-containing copolymer (a) has a fluorine content of 10% by weight or more based on a fluoroolefin unit, preferably
10 to 70% by weight, more preferably 15 to 50% by weight, having an intrinsic viscosity of 0.01 to 4.0 dl / g measured in tetrahydrofuran in an uncured state is used.

If the fluorine content is less than 10% by weight, the intended effect of improving weather resistance is reduced. Further, when the intrinsic viscosity is within the above range, the paintability as a coating material is good, and the physical properties of the formed film are also excellent.

As such a fluorine-containing copolymer, a copolymer obtained from “an ethylenically unsaturated compound as a comonomer copolymerizable with a fluoroolefin” and “fluoroolefin” is preferably employed.

Further, as the ethylenically unsaturated compound as a monomer copolymerizable with a fluoroolefin, olefins,
Examples thereof include vinyl ethers, vinyl esters, allyl ethers, allyl esters, and compounds containing a (meth) acryloyl group.

Among them, olefins having excellent copolymerizability with fluoroolefins, vinyl ethers, vinyl esters, allyl ethers having a linear, branched or alicyclic alkyl group having about 1 to 10 carbon atoms. Is preferred.

The fluorinated copolymer (a) contains 30 to 70 mol% of a unit based on a fluoroolefin. If it is less than 30 mol%, the effect of improving weather resistance is not sufficient, and if it is more than 70 mol%, the solubility in a solvent tends to decrease, which may hinder the application work as a paint. In the copolymer, the fluoroolefin and the ethylenically unsaturated compound may be used alone or in combination of two or more.

The fluorinated copolymer (a), which is a main component of the paint of the present invention, having a crosslinked site, reacts with another component, a curing agent, or the copolymer to form a three-dimensional network structure, A film having a cross-linking site is preferably employed because it gives a favorable result of improving the solvent resistance, acid resistance and alkali resistance of the coating.

As the crosslinking site, a hydroxyl group, a carboxylic acid group, an acid amide group, an amino group, an active hydrogen-containing group such as a mercapto group,
Examples include an epoxy group, a carbon-carbon unsaturated group, a bromine atom, and an active halogen atom such as iodine. Among these, the active hydrogen-containing group is preferable in that it has excellent reactivity with isocyanate-based curing agents, aminoplast-based curing agents, and the like which are usually used as a curing agent, and a hydroxyl group is particularly preferred.

The method of introducing such a cross-linking site into the copolymer includes, for example, the cross-linking of hydroxyalkyl vinyl ether, hydroxyalkyl aryl ether, hydroxyaryl vinyl ether, hydroxyalkyl allyl ether, glycidyl vinyl ether, (meth) acrylic acid, aryl vinyl ether, diaminoethyl vinyl ether, etc. A method in which a monomer having a reactive site is copolymerized, or a method in which an acid anhydride, an isocyanate, an alkyl (meth) acrylate, or the like is added to a fluorinated copolymer by reacting the same is employed.

Further, as a method for decomposing a part of the copolymer, after copolymerizing a monomer having a hydrolyzable ester bond, a carboxylic acid group or a carboxylic acid group in the copolymer is obtained by hydrolyzing the copolymer. A method of generating a hydroxyl group is also employed. Furthermore, a method of introducing a carboxylic acid group by reacting a divalent carboxylic anhydride such as succinic acid with a hydroxyl group-containing copolymer is also employed.

The acrylic polymer (b) compatible with the fluorinated copolymer (a), which is a main component of the paint of the present invention, is an alcohol ester of (meth) acrylic acid having 1 to 12 carbon atoms, It is an acrylic polymer having a molecular weight of 500 to 80,000.

Monomers for constituting such an acrylic polymer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl methacrylate,
Examples include tert-butyl (meth) acrylate and (meth) acrylonitrile.

Preferably, a copolymer of two or more of these monomers, or a copolymer with an alcoholic ester of acrylic acid other than those described above, styrene, maleic acid, vinyl esters (eg, vinyl acetate), vinyl silane, or the like is used. Coalescing is used. More preferably, in the acrylic polymer, a polymer having a cross-linking site is cross-linked by a reaction with a cross-linking site of a fluorinated copolymer, and a coating film of the coating material has a three-dimensional network structure and exhibits excellent characteristics.

Here, the cross-linking site in the acrylic polymer (b) is preferably a hydroxyl group, a glycidyl group, an amide group, a silanol group, or the like.
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth)
Acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3
-Chloro-2-hydroxypropyl (meth) acrylate, etc., and glycidyl group introduced by glycidyl (meth)
Acrylate, 2,3-epoxy-2-methylpropyl (meth) acrylate, etc., and further, an amide group is introduced by (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-tert-butyl (meth) acrylamide, N -Introduction of octyl (meth) acrylamide, diacetone (meth) acrylamide, and the like, and silanol group is carried out by copolymerizing a monomer such as vinylsilane with a comonomer that gives the above-mentioned acrylic polymer or copolymer. Done.

The silanol group can also be introduced by a method of adding an isocyanate silane or a silane coupling agent to a hydroxyl group-containing acrylic polymer.

Here, the acrylic polymer (b) may be a mixture of a polymer having a cross-linking site and a polymer having no cross-linking site. It does not include a copolymer with a monomer having a hydroxyl group, a glycidyl group, an amide group, or the like. The proportion of the acrylic polymer having no cross-linking site is preferably up to 50% by weight based on the acrylic polymer having the cross-linking site.

Further, a curing agent can be blended with (a) and (b), which are main components of the coating material, and are compatible with the fluorinated copolymer (a) and the acrylic polymer (b),
What cures them is used.

As the curing agent, polyisocyanates, for example, non-yellowing diisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate, and adducts thereof, and blocked isocyanates in which isocyanate groups are blocked with a blocking agent such as phenol are preferably used. sell. Also, various curing agents such as melamine, metal alkoxide, urea resin, polybasic acid, epoxy, and silanol can be used.

Here, when the crosslinking site of the fluorinated copolymer (a) is a hydroxyl group, a polyisocyanate-based or metal alkoxide-based is preferred. As the melamine-based curing agent, melamine partially etherified with one or more lower alcohols such as methanol, ethanol, propanol, and butanol is particularly preferable. Such a curing agent has a very useful effect on formation of a three-dimensional network structure of a copolymer or a polymer having a crosslinking site.

For the purpose of promoting curing together with the curing agent, a catalyst may be used in combination.For example, dibutyltin dilaurate is used as an isocyanate-based curing agent, and a paratoluenesulfonic acid-based catalyst is used as a melamine-based curing agent. It is used in a proportion of 0.001 to 2 parts by weight based on 100 parts by weight of the copolymer (a).

The respective proportions of the main constituent components in the paint of the present invention are preferably from 30 to 90% by weight of the fluorinated copolymer (a) and from 10 to 70% by weight of the acrylic polymer (b). When the amount of the fluorine-containing copolymer (a) is small, the fluorine content decreases, and the intended effect of improving weather resistance is not achieved.
When the amount of the acrylic polymer (b) is small, the adhesiveness to the substrate decreases.

Each of the fluorinated copolymer (a) and the acrylic polymer (b) is not limited to one type within the range of the above ratio, and two or more types may be used in combination.

The curing agent is used in an amount of 0 to 20% by weight based on the total amount of the fluorinated copolymer (a) and the acrylic polymer (b).

In the paint, in addition to the main constituent components, 0.5 to the total amount of the fluorine-containing copolymer (a) and the acrylic polymer (b) is used.
The weather resistance can be further improved by including up to 3% of an ultraviolet absorber.

As the ultraviolet absorber, conventionally known or well-known 2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4- (1-methyl-2-hydroxy) Ethoxybenzophenone, 2-hydroxy-4
Benzophenones such as-(2-hydroxy-3-methacryloxy) propoxybenzophenone;
(2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-
A benzotriazole-based compound such as (tert-butylphenyl) benzotriazole is used alone or in combination.

Further, "acrylic polymer (c) having a fluoroalkyl group" (hereinafter, simply referred to as acrylic polymer (c)) may be added to such a paint to improve the water repellency of the soft PVC sheet. . As the acrylic polymer (c), it is preferable to employ a polymer having a crosslinked site similar to that of the fluorinated copolymer (a) or the acrylic polymer (b) because water repellency and the like are maintained for a long time. . The amount of the acrylic polymer (c) added is a total of 10% of the fluorine-containing copolymer (a) and the acrylic polymer (b).
It is preferable to employ in the range of about 0.1 to 30 parts by weight per 0 parts by weight.

In addition, for the purpose of improving the properties, paints include, for example, an antifoaming agent, an antistatic agent, a pigment, a dispersion stabilizer, a viscosity modifier,
Additives such as a leveling agent and an anti-gelling agent may be added. The compounding of the pigment has the effect of shading the coating. In addition, a primer can be used for the purpose of obtaining necessary folding adhesion.

The coating material of the present invention comprises the above-mentioned main components such as the fluorinated copolymer (a) and the acrylic polymer (b), and if necessary, a curing agent, an ultraviolet absorber, and an acrylic polymer (c). It can be obtained by dissolving other additives in an organic solvent.

Examples of the solvent used include aromatic hydrocarbons such as toluene and xylene; alcohols such as propanol and butanol; esters such as ethyl acetate and butyl acetate; ketones such as methyl ethyl ketone and methyl isobutyl ketone; and glycols such as ethyl cellosolve. Various general organic solvents such as ethers and various commercially available thinners can be used. The concentration of the paint component is 1 to
Adjustment to 60% by weight, preferably 5 to 50% by weight is suitable for workability of forming a coating.

When adjusting the paint, for example, ball mill, paint shaker, sand mill, jet mill, three rolls,
It is carried out by using various devices used for ordinary coating, such as a kneader, and is not particularly limited. At this time, additives such as those described above can be added.

In the present invention, a method of forming a coating film of a paint on a soft PVC sheet is performed by brushing the paint on the sheet, spraying, applying by a flow coater, or by applying the sheet by immersing the sheet in the paint to remove the solvent. The film is dried sufficiently to evaporate, and then heated or left at room temperature to form a film. In this case, the heat treatment is performed at a temperature lower than the temperature at which the sheet is not deformed, for example, treatment at 60 ° C. for 10 minutes is sufficient. A sufficient effect is recognized when the thickness of the formed coating film is 2 to 100 μm. The adjustment of the thickness of the film is determined by the component concentration of the paint and the application conditions, but there is no problem even if it is formed into a multilayer film. The shape of the sheet is not limited at all.

[Examples] Examples 1 to 10 (all examples), Examples 11 to 13 (all comparative examples) Fluorine-containing copolymer (a), acrylic copolymer (b), acrylic shown in Table 1 Polymer (c), solvent (d)
Paints 1 to 12 having compositions (numerical parts by weight) composed of xylene, isocyanate-based curing agent (e), and benzophenone-based ultraviolet absorber (f).

Coatings 1 to 12 are applied to the surface of the soft PVC sheet by adjusting the thickness of the coating formed by a gravure coater to 15 μm, dried at room temperature, and then heated at 60 ° C. for 10 minutes to form a cured coating. Was formed.

Table 2 shows the results of the following evaluation tests performed on the sheet on which the coating was formed.

Contact angle: The contact angle of water and n- hexadecane (in the table referred to as C ₁₆₎ (unit: °) is measured.

Adhesion: The adhesion of the coating is measured in accordance with the method of ASTM-3359 initially, after immersion in warm water (60 ° C. × 30 days), and after treatment for 1000 hours with a sunshine weather meter, and evaluated based on the number of squares remaining.

Weather resistance: Measured with a color measuring instrument (SM-3 manufactured by Suga Test Instruments Co., Ltd.) before and after the treatment with the sunshine weather meter for 1000 hours, and the yellowing deterioration thereof is determined as a difference (ΔY.I) before and after the treatment.

In Table 1, the fluorinated copolymer (a) and acrylic polymer (b) used are as follows.

FA: A copolymer having a ratio of TFE / HBVE / n-BVE = 48.1 / 12.5 / 39.4 (% by weight) having an intrinsic viscosity (referred to as [η]) of 0.15 dl / measured at 30 ° C. in tetrahydrofuran. g (hereinafter the same).

FB: CTFE / HBVE / CHVE / EVE = 56.4 / 5.7 / 12.4 / 25.5,
[Η] = 0.21 dl / g.

_{F-C: TFE / CH 3} COOCH = CH 2 / CH 2 = CHCH 2 OCH 2 CH 2 OH = 53.7 /
23.1 / 23.2, [η] = 0.18 dl / g.

FD: CTFE / EVE / HBVE / Vova 9 = 39.4 / 17.2 / 9.5 / 33.9,
[Η] = 0.40 dl / g.

F-E: TFE / EVE / HBVE / CH ₂ = CHOCH ₂ CF ₂ CF ₂ H = 57.0 / 22.4 / 1
0.8 / 9.8, [η] = 0.10 dl / g.

(However, TFE is tetrafluoroethylene, HBVE is ω-
Hydroxybutyl vinyl ether, n-BVE is n-butyl vinyl ether, CTFE is chlorotrifluoroethylene, CHVE is cyclohexyl vinyl ether, EVE is ethyl vinyl ether, and Beova 9 is a fatty acid having a branched alkyl group manufactured by Shell Chemical Company (C 9 ) Vinyl ester. M-1) Copolymer copolymerized at a ratio of isobutyl methacrylate / n-butyl acrylate / 2-hydroxyethyl methacrylate = 7/2/1 (molar ratio) (hereinafter the same).

M-2: methyl acrylate / n-butyl acrylate / glycidyl acrylate = 8/1/1.

M-3: n-butyl methacrylate / isobutyl methacrylate / acrylonitrile / 2-hydroxyethyl methacrylate = 1/7/1/1.

M-4: methyl methacrylate / n-butyl methacrylate = 5/5.

In addition, the acrylic polymer (c) is CH ₂ = CHCOOCH ₂ CH ₂
(CF ₂ ) ₁₀ F / isobutyl methacrylate / n-butyl acrylate / 2-hydroxyethyl methacrylate = 20/60 /
10/10% by weight copolymer, isocyanate-based curing agent is Coronate EH (manufactured by Nippon Polyurethane),
Benzophenone UV absorber is Biosorb 130
(Manufactured by Kyodo Yakuhin).

Example 14 (Example) The same operation as in Example 1 was carried out except that the drying conditions were changed to 120 ° C. for 1 minute, and the same effect as that in Example 1 was obtained.

[Effects of the Invention] The flexible PVC sheet of the present invention has durability, since a coating of a specific paint is formed while maintaining good adhesion.
It is extremely excellent in antifouling properties.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B32B 1/00-35/00 C08J 7/04-7/06 B05D 1/00-7/26

Claims (4)

(57) [Claims] 1. A fluorine-containing copolymer (a) containing 30 to 70 mol% of a unit based on a fluoroolefin composed of tetrafluoroethylene and / or chlorotrifluoroethylene on a soft vinyl chloride sheet and having a crosslinking site, and A soft PVC sheet formed by forming a coating film of a paint containing an acrylic polymer (b) as a main component which is compatible with (a). 2. The flexible PVC sheet according to claim 1, wherein the acrylic polymer (b) has a crosslinking site. 3. The flexible PVC sheet according to claim 1, wherein the coating further contains an acrylic polymer (c) having a fluoroalkyl group. 4. The flexible PVC sheet according to claim 1, wherein the paint further comprises a curing agent.