JP2830045B2 - Rigid PVC sheet - Google Patents

Description

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

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

[Problems to be Solved by the Invention] Conventionally, there has been a rigid PVC sheet having an excellent antifouling property in which an acrylic resin is coated or an acrylic film is laminated. However, these have poor adhesion between the protective coat and the sheet and are not sufficiently usable.

An object of the present invention is to solve the above-mentioned problems of the prior art, that is, to provide a hard PVC sheet having excellent weather resistance and antifouling property for a long period of time, and excellent adhesion of a protective coat.

Means for Solving the Problems The present invention provides a rigid PVC sheet containing 30 to 70 mol% of a unit based on a fluoroolefin selected from the group consisting of tetrafluoroethylene and chlorotrifluoroethylene, and having a crosslinked site. Having fluorine-containing copolymer (a)
And a hard PVC sheet formed by forming a coating film of a paint mainly containing an acrylic polymer (b) compatible with (a).

Examples of the vinyl chloride resin as a base material of the rigid PVC sheet of the present invention include vinyl chloride, vinyl acetate, ethylene, propylene, (meth) acrylate [acrylate and methacrylic acid] in addition to vinyl chloride homopolymer. Esters are thus collectively referred to, as well as others. And at least 40% by weight, preferably 30% by weight or less, 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.

The vinyl chloride resin may contain an appropriate amount of a plasticizer. Examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, diisodecyl adipate, tricresyl phosphate, epoxidized soybean oil, and epoxidized linseed oil. And the like.

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.

The shape may be a wave shape, a plate shape, or a ribbon shape.

In the present invention, the coating material for forming a film on the above-mentioned rigid PVC sheet includes "a unit based on a fluoroolefin selected from the group consisting of tetrafluoroethylene and chlorotrifluoroethylene in an amount of 30 to 70 mol% and having a crosslinked site. The main component is a fluorine-containing copolymer (a) [hereinafter simply referred to as a fluorine-containing copolymer (a)] and an acrylic polymer (b) compatible with (a).

Here, the fluorine-containing copolymer (a) has a fluorine content of 10% by weight based on a “fluoroolefin selected from the group consisting of tetrafluoroethylene and chlorotrifluoroethylene” (hereinafter simply referred to as fluoroolefin) unit. The solvent-soluble fluorine-containing copolymer described above is preferably employed.

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

Since the fluorine-containing copolymer (a), which is a main component of the paint of the present invention, has a crosslinked site, it reacts with other components, a curing agent, or the copolymer to form a three-dimensional network structure and form a film. Gives a favorable result that the solvent resistance, acid resistance and alkali resistance of the polymer are improved.

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 epoxy groups, carbon-carbon unsaturated groups, active halogens such as bromine and iodine. Of these, active hydrogen-containing groups are preferred in that they have excellent reactivity with isocyanate-based curing agents, aminoplast-based curing agents, and the like, which are usually used as curing agents, and hydroxyl groups are 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.

In addition, as a method of decomposing a part of the copolymer, after copolymerizing a monomer having a hydrolyzable ester group, 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, the hydroxyl group-containing copolymer may be added with 2 such as succinic acid.
A method in which a carboxylic acid anhydride is reacted to introduce a carboxylic acid group 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.

For example, the introduction of a hydroxyl group is performed by 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl (meth) acrylate,
-Hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, etc., and glycidyl group is introduced by glycidyl (meth) Acrylate, 2,3-epoxy-2-methylpropyl (meth) acrylate, etc.
Furthermore, the introduction of an amide group is (meth) acrylamide, dimethyl (meth) acrylamide, N-tert-butyl (meth) acrylamide, N-octyl (meth) acrylamide, diacetone (meth) acrylamide, and the introduction of a silanol group is vinylsilane. And a comonomer that gives the acrylic polymer or copolymer described above.

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, it is of course possible to mix a curing agent with the main components (a) and (b) of the paint,
Fluorine-containing copolymer (a) and acrylic polymer (b)
And those that harden them are used.

As such a 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. Can. In addition, melamine, metal alkoxide, urea resin, polybasic acid, epoxy,
Various curing agents such as silanols can also 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 of lower alcohols such as methanol, ethanol, propanol, and butanol is preferably used. 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 accelerating the curing together with the curing agent, a catalyst may be used in combination.Examples of such curing assistants include dibutyltin dilaurate as an isocyanate-based curing agent and a paratoluenesulfonic acid-based catalyst as a melamine-based curing agent. It is used in an amount of 0.001 to 2 parts by weight based on 100 parts by weight of the fluorocopolymer (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). If the amount of the fluorinated copolymer (a) is small, the fluorine content is reduced, and the intended effect of improving the weather resistance is not achieved. Decrease.

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

The curing agent is used at a ratio of 0 to 20% by weight based on the total amount of the fluorine-containing copolymer (a) and the acrylic polymer (b).

In the coating material, in addition to the main constituent components, the amount of the fluoropolymer (a) and the acrylic polymer (b) was set at 0.
The weather resistance can be further improved by including 5 to 20% 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 (t-butylphenyl) benzotriazole is used alone or in combination.

Further, an acrylic polymer (c) having a fluoroalkyl group (hereinafter, simply referred to as an acrylic polymer (c)) may be added to such a coating material to improve the water repellency of the rigid PVC sheet. When the acrylic polymer (c) has a crosslinking site similar to that of the fluorinated copolymer (a) or the acrylic polymer (b),
It is preferable because water repellency and the like are maintained for a long time.

The addition amount of the acrylic polymer (c) is 10% of the total amount 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 also be used for the purpose of obtaining the necessary scratch adhesion.

The coating material of the present invention is a fluorine-containing copolymer (a) as described above.
It can be obtained by dissolving main constituent components such as acrylic polymer (b) and, if necessary, a curing agent, an ultraviolet absorber, an acrylic polymer (c) and 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 ethyl cellosolve. Various general organic solvents such as glycol ethers and various commercially available thinners are exemplified. The concentration of the paint component is 1
It is preferable in terms of workability to form a coating that the content is adjusted to 60% by weight, preferably 5% to 50% by weight.

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 rigid PVC sheet is performed by brushing the paint on the sheet, spraying, applying by a flow coater, or by applying the solvent 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, Comparative Examples 1 to 3 Fluorine-containing copolymer (a), acrylic copolymer (b), acrylic polymer (c), solvent (d) shown in Table 1 )
Paints 1 to 12 having compositions (numerical parts by weight) composed of xylene, isocyanate-based curing agent (e), and benzophenone-based ultraviolet absorber (f).

The coatings 1 to 12 are applied to the surface of the rigid PVC sheet by adjusting the thickness of the coating formed by a flow 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 11 The same operation as in Example 1 was performed, except that the drying conditions were changed to 120 ° C. for 1 minute, and the same effects as in Example 1 were obtained.

[Effects of the Invention] The rigid PVC sheet of the present invention is extremely excellent in weather resistance because a coating of a specific paint is formed while maintaining good adhesion.

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 fluorinated copolymer (a) containing 30 to 70 mol% of a unit based on a fluoroolefin selected from the group consisting of tetrafluoroethylene and chlorotrifluoroethylene and having a crosslinked site on a rigid PVC sheet. )
And a hard PVC sheet formed by forming a coating film of a paint containing, as a main component, an acrylic polymer (b) compatible with (a). 2. The hard PVC sheet according to claim 1, wherein the acrylic polymer (b) has a cross-linking site. 3. The hard PVC sheet according to claim 1, wherein the coating further contains an acrylic polymer (c) having a fluoroalkyl group. 4. The hard PVC sheet according to claim 1, wherein the paint further contains a curing agent.