JP3167010B2 - Coating composition for plasticized vinyl chloride resin and molded article of plasticized vinyl chloride resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition for a plasticized vinyl chloride resin, and more particularly, to the prevention of bleed-out of a plasticizer to prevent contamination of the surface of a molded product, as well as flexibility, weather resistance, and the like. The present invention relates to a coating composition suitable for producing a plasticized vinyl chloride resin molded article having excellent water resistance, solvent resistance, adhesiveness and the like.

[0002]

2. Description of the Related Art Conventionally, vinyl chloride resins have been inexpensive,
A resin with excellent chemical stability that can be used over a wide range from hard to soft by changing the amount of plasticizer added, such as interior materials such as PVC wallpaper, floor and ceiling materials, sheets for agricultural use, sheets for tents and canvas, etc. It is used in many applications as materials, molded products such as hoses and tubes. However, plasticized vinyl chloride resin contains a large amount of plasticizer, and the plasticizer bleeds out to the surface over time,
There are drawbacks such as adhesion of dirt and blocking.

Various methods have been studied for preventing bleed-out of a plasticizer from a plasticized vinyl chloride resin. For example, Japanese Patent Publication No. 47-28740 proposes a method of providing a resin coating layer on a surface of a plasticized vinyl chloride resin molded product for suppressing migration of a plasticizer to the surface. As a resin forming such a resin coating layer, homopolymers of acrylic acid esters or methacrylic acid esters, copolymers thereof, and the like are known, but in these polymers, the bleed out of the plasticizer is sufficiently prevented. No,
Stain resistance, blocking resistance, bending resistance, and the like are not satisfactory.

[0004] Also, Japanese Patent Application Laid-Open No. 2-29838 discloses that
There has been proposed a method of forming a coating film of a fluorine-based copolymer and an acrylic copolymer having a cross-linked site having excellent adhesion on the surface of a plasticized vinyl chloride resin sheet. The effect of preventing out is small.

[0005]

By the way, ethylene-
A vinyl alcohol copolymer (hereinafter referred to as an EVOH resin) is widely known as a resin having excellent solvent resistance, coating strength, abrasion resistance, gas barrier properties, and the like, and is a point of preventing bleed out of a plasticizer. Is a preferred material. However, since it is poor in flexibility, it causes cracking and whitening at the time of bending, and it is not satisfactory in workability because it has adhesiveness and dissolves in only a part of the solvent.

Accordingly, an object of the present invention is to prevent bleed-out of a plasticizer to prevent contamination and blocking of the surface of a molded product, and to provide a plasticized vinyl chloride resin molded product with flexibility, adhesion, water resistance and solvent resistance. An object of the present invention is to provide a coating composition for a plasticized vinyl chloride resin which also imparts properties, weather resistance and the like. Conventionally, for plasticizing vinyl chloride resins, ester compounds and polyester resins have been used as plasticizers. Therefore, it is clear that the ester bond contributes to the plasticization of the vinyl chloride resin and the compatibility with the resin. The present inventors have made intensive studies based on the above findings to introduce an ester bond into an EVOH resin, and have reached the present invention.

[0007]

The above objects of the present invention are attained by the following present invention. That is, the present invention consists of 95 to 5% by weight of an ethylene-vinyl alcohol copolymer and 5 to 50% by weight of an aliphatic polyester. A coating composition for a plasticized vinyl chloride resin, which comprises a copolymer resin.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to embodiments. The ethylene-vinyl alcohol copolymer resin (hereinafter sometimes referred to as a graft resin) used in the present invention is obtained by grafting an aliphatic polyester onto a vinyl alcohol portion of an ethylene-vinyl alcohol copolymer (EVOH resin). It is a thermoplastic resin. The graft resin of the present invention can be prepared, for example, by subjecting a lactone to ring-opening polymerization in the presence of an EVOH resin,
It can be produced by, for example, a method of reacting H with a polyester having a carboxyl group at a terminal obtained by ring-opening polymerization of an aliphatic polyester or a lactone produced by a condensation polymerization reaction. Hereinafter, the former method will be described.

The EVOH resin used to produce the graft resin in the present invention is a resin obtained by partially saponifying vinyl acetate of an ethylene-vinyl acetate copolymer resin. From the viewpoint of the moldability and gas barrier properties of the graft resin, the preferred ethylene content is 20 to 60 mol%, more preferably 2 to 60 mol%.
5 to 55 mol%, and 90% of vinyl acetate in the polymer chain.
It is preferred that at least 95% by mole, more preferably at least 95% by mole, be saponified. If the ethylene content is less than 20 mol%, the moldability deteriorates and the gas barrier property under high humidity deteriorates. On the other hand, if the ethylene content exceeds 60 mol%, the gas barrier properties characteristic of the EVOH resin are lost, which is not preferable.

In the present invention, the lactone to be reacted with the EVOH resin is a lactone such as ε-caprolactone and δ-valerolactone, which can form a polyester by a conventionally known lactone ring-opening polymerization method. A method for ring-opening polymerization of lactones in the presence of an EVOH resin is known as EVOH.
Since a resin obtained by grafting a polyester to a resin can be easily obtained by a single-step reaction, the method is simple and preferable because it involves fewer steps than a method in which a polyester is formed in advance by a ring-opening polymerization or a condensation polymerization reaction and then reacted with an EVOH resin.

The lactone used in the present invention is not particularly limited as long as it undergoes ring-opening polymerization, but ε-caprolactone and δ-valerolactone are particularly preferred. Examples of ε-caprolactone include ε-caprolactone, monomethyl-ε-caprolactone, monoethyl-ε-caprolactone, monopropyl-ε-caprolactone, monododecyl-ε-caprolactone and the like.
About 5 to about 5 monoalkyl-ε-caprolactones, or dialkyl or trialkyl-ε-caprolactones in which 2 to 3 alkyl groups are substituted with hydrogen of the same or different carbon atom other than the carbon atom at the ε-position And substituted ε-caprolactones in which the substituent is an alkoxy group, an aryl group, a benzyl group, a cycloalkyl group, an aralkyl group, or the like.

The δ-valerolactones include 5-valerolactone, 3-methyl-5-valerolactone,
3, -dimethyl-5-valerolactone, 2-methyl-5
-Valerolactone, 3-ethyl-5-valerolactone and the like.

The ring-opening polymerization reaction of lactones in the presence of an EVOH resin is carried out in a reaction vessel at 95 to 50% by weight of the EVOH resin.
And a lactone in an amount of 5 to 50% by weight, preferably in a nitrogen stream, using a conventionally known ring-opening polymerization catalyst, for example, a titanium compound or a tin compound at a temperature of 10 to 220 ° C. Preferably, the reaction is performed at a temperature of 80 to 220 ° C. with stirring for several hours. It is also possible to carry out polymerization in a heated and melted state in a kneading machine such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, a Brabender and the like.

Thus, the EVOH resin (ethylene-
An ethylene-vinyl alcohol-based copolymer resin obtained by grafting an aliphatic polyester onto (vinyl alcohol copolymer resin) is obtained. In the above method, the mixture of the EVOH resin powder and the liquid lactone compound is merely a mechanical mixture, and the mixing state at the beginning of the reaction is not uniform, but as the reaction proceeds, a uniform solution or a reaction product in a molten state is formed. Thus, the graft resin (ethylene-vinyl alcohol copolymer resin) of the present invention in which the aliphatic polyester is grafted on the EVOH resin is obtained.

The ethylene-vinyl alcohol copolymer resin used in the present invention obtained as described above has an ethylene-vinyl alcohol copolymer having a trunk content of 9%.
The graft copolymer resin is 5 to 50% by weight and the content of the aliphatic polyester grafted to the trunk is 5 to 50% by weight. This graft copolymer resin has the solvent resistance, high strength, abrasion resistance and gas barrier properties (prevention of bleed-out of plasticizer) of the EVOH resin and the flexibility, flex resistance and adhesion properties of the polyester resin. Have both.

When the content of the EVOH resin exceeds 95% by weight and the content of the polyester resin is less than 5% by weight, the bleed-out prevention performance of the plasticizer is excellent, but the adhesion to the plasticized vinyl chloride resin is improved. , Flexibility and bending resistance are reduced. When the content of the EVOH resin is less than 50% by weight,
When the content of the polyester resin exceeds 50% by weight, the adhesiveness with the plasticized vinyl chloride resin, flexibility, and bending resistance are excellent, but the bleed out prevention performance of the plasticizer is reduced.

The coating composition for a plasticized vinyl chloride-based resin of the present invention containing the ethylene-vinyl alcohol-based copolymer obtained as described above is produced by blending various additives as necessary. Additives include color pigments, extenders, UV absorbers, UV stabilizers, colloidal silica,
Dispersants, fungicides, matting agents and the like are used. The coating composition of the present invention is produced by mixing and dispersing a solid-state or solution-state ethylene-vinyl alcohol-based copolymer with additives and the like using a conventionally known mixer, disperser, or the like.

By using the coating composition of the present invention,
A film excellent in flexibility, water resistance, solvent resistance, bleed out prevention of plasticizer (gas barrier property), solvent resistance, film strength, etc. can be obtained. Can be crosslinked with various crosslinking agents to obtain a film having more excellent heat resistance, water resistance, solvent resistance, mechanical strength, prevention of bleed out of a plasticizer, and the like. Any crosslinking agent that reacts with a hydroxyl group can be used, and examples thereof include a phenol resin, a melamine resin, an epoxy resin, and an isocyanate group-containing compound.

As a method of forming a coating film of the coating composition of the present invention on the surface of a plasticized vinyl chloride resin molded article, for example, when the composition is a solution, it is adjusted to an appropriate concentration.
In the case of a solid state, after dissolving in various solvents, for example, a method of forming a coating using a coating method such as gravure coater, knife coater, reverse coater, dipping, brush coating, air spray, airless spray, etc. No. As the solvent, for example, ethylene glycol,
Glycols such as glycerin and diethylene glycol,
Dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), a mixed solution of a lower alcohol and water, and the like can be used, but a mixed solution of a lower alcohol and water is preferable for practical use.

As another method for forming a film, a method of directly melt-molding the ethylene-vinyl alcohol-based copolymer resin of the present invention to form a film and a sheet and laminating the film on a plasticized vinyl chloride-based resin molded product is used. Can be. Upon lamination, heat lamination may be directly performed by a conventionally known method, or lamination may be performed via various adhesives such as urethane and acrylic.

The plasticized vinyl chloride resin molded article coated with the ethylene-vinyl alcohol copolymer resin film of the present invention is made of PVC wallpaper, PVC sheet, desk mat, PVC leather, PVC film, PVC hose tube. Very useful as etc.

[0022]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the text and table, “parts” are based on weight.

Production Examples 1 to 3 An EVOH resin having a composition having an ethylene content of 31.5 mol% and a degree of saponification of a vinyl acetate portion of 98.5 mol% and ε-caprolactone were charged into a flask at the ratios shown in Table 1. Further, 0.1 part of tetrabutyl titanate was added per 100 parts of ε-caprolactone, and the mixture was heated at 1 ° C./2 to 3 minutes while stirring under a nitrogen stream. At 160 to 170 ° C., the heterogeneous system becomes a homogeneous solution gradually,
At ~ 200 ° C, a completely homogeneous system was obtained. 200-220 ° C
The reaction was continued for 6 hours to obtain a graft resin of the present invention.

The physical properties of the graft resins obtained in the respective Production Examples were evaluated, and the results are shown in Table 1. Each physical property was evaluated by the following methods. (1) Hardness A sheet obtained by press-molding each resin at a temperature of 170 ° C. is subjected to an A-type hardness tester (JIS) based on JIS K-6301.
-A) and a D-type hardness tester (Rockwell). (2) Strength properties Press-formed sheets of each resin are JIS K-7311-3
A 100% modulus, tensile strength and elongation were measured according to the same JIS. (3) Vicat softening point The softening point of each resin was measured according to JIS K-7206.

[0025]

[Table 1]

Examples 1 to 3 Each of the resins obtained in Production Examples 1 to 3 was dissolved in a mixed solvent of isopropyl alcohol (IPA) / water = (3/7 weight ratio), and the weight of the solid component was 20%. A combined solution was obtained. This polymer solution was applied to both sides of a soft vinyl chloride sheet (thickness: 3 mm) by a bar coater so that the film thickness after drying was 10 to 20 μm, and dried at 80 ° C. for 30 seconds to form a coating. A test was performed on the resin-coated soft vinyl chloride sheet by the following method.

(1) Bleed-out amount of plasticizer A soft vinyl chloride sheet cut to 50 mm x 50 mm is sandwiched between polyethylene sheets whose weight has been measured in advance, further sandwiched between glass sheets, and a load of 5 kg is applied in this state.
Leave for 24 hours in a thermostat kept at 70 ° C. afterwards,
After taking out from the thermostat, the polyethylene sheet is peeled off, and the weight of the polyethylene sheet is measured. The smaller the value of the weight gain of the polyethylene sheet, the smaller the amount of bleed-out of the plasticizer from the soft vinyl chloride sheet.

(2) Stain resistance A soft vinyl chloride sheet cut to 50 mm × 50 mm is brought into close contact with a copy sheet which has been exposed in advance, sandwiched between glass plates, a load of 3 kg is applied in this state, and the temperature is maintained at 50 ° C. Let stand for 24 hours and 72 hours in the thermostat. afterwards,
After taking out from the thermostat, the sheet is peeled off from the copy paper, and the degree of contamination of the sheet is visually observed. Observation results are shown as ○: no contamination △: partial contamination ×: whole contamination.

(3) Adhesion The coating film was cut into 100 squares of 1 mm square with a knife and subjected to a peeling test with a cellophane tape. (4) Flexibility The soft vinyl chloride sheet was bent 20 times at room temperature, and the state of the coating film was visually observed. Observation results are indicated by ○: no change △: whitened ×: cracked

Examples 4-5 A solution obtained by adding a self-emulsifying polyisocyanate (Nippon Polyurethane) to a polymer solution of the resins of Production Examples 2 and 3 used in Examples 1 to 3 was used as Examples 1 to 3. Similarly, it was applied to a soft vinyl chloride sheet and dried at 80 ° C. for 30 seconds. After one day at room temperature, the same tests as in Examples 1 to 3 were performed.

Examples 6 to 8 The resin obtained in Production Examples 1 to 3 was melt-extruded with a T-die using an extruder having a D (diameter) of 60 mm to produce a film having a thickness of 20 μm. A resin-coated soft vinyl chloride sheet was prepared by laminating the soft vinyl chloride sheet, and the same test as in the above example was performed.

Comparative Example 1 A DMSO solution (solid content: 15%) of the EVOH resin used in the production example was dried on a soft vinyl chloride sheet to a thickness of 10%.
The coating was performed in the same manner as in the above example so as to have a thickness of ２０20 μm. The same test as in each example was performed on the obtained resin-coated soft vinyl chloride sheet.

Comparative Example 2 A film having a thickness of 20 μm was produced in the same manner as in Examples 6 to 8 using the EVOH resin used in the production example, and this was laminated to a soft vinyl chloride sheet with a polyurethane-based adhesive. The same test as in each example was performed on the obtained resin-coated soft vinyl chloride sheet.

Comparative Example 3 A soft vinyl chloride sheet mixed with a fluororesin for vinyl chloride (Fluorotop manufactured by Asahi Glass Co., Ltd.) and a curing agent (Coronate HX manufactured by Nippon Polyurethane Co., Ltd.) was dried to a thickness of 10%. The same test as in each example was performed on the obtained fluororesin-coated soft vinyl chloride sheet coated so as to have a thickness of 20 μm. Table 2 shows the test results of the above Examples and Comparative Examples.

[0035]

[Table 2]

[0036]

According to the present invention described above, the coating composition for a plasticized vinyl chloride resin containing the ethylene-vinyl alcohol copolymer resin of the present invention is characterized in that the plasticizer contained in the plasticized vinyl chloride resin is Provides an excellent coating that prevents bleed-out and prevents contamination of the molded article surface.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // C08F 210/02 C08F 210/02 216/06 216/06 C09D 129/04 C09D 129/04 (72) Inventor Katsumi Kuriyama Tokyo 1-7-6 Bakurocho, Nihombashi, Chuo-ku, Tokyo Dainichi Seika Kogyo Co., Ltd. (56) References JP-A-48-76941 (JP, A) JP-A-58-91756 (JP, A) JP-A-1-313507 (JP, A) JP-A-8-337642 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 131/00 C08F 8/14 C08J 7/04 CEV C09D 123/08 C09D 167/04 C08F 210/02 C08F 216/06 C09D 129/04

Claims (6)

(57) [Claims] 1. An ethylene-vinyl alcohol copolymer 9.
A plasticizer comprising 5 to 50% by weight of an aliphatic polyester and 5 to 50% by weight of an aliphatic polyester, wherein the ethylene-vinyl alcohol copolymer contains the ethylene-vinyl alcohol copolymer resin represented by the graph of the aliphatic polyester. A coating composition for a vinyl chloride resin. 2. The ethylene-vinyl alcohol copolymer according to claim 1, wherein the ethylene content is 20 to 60% by mole, the balance is vinyl acetate, and 90% by mole or more of the vinyl acetate portion is saponified. Coating composition for plasticized vinyl chloride resin. 3. The coating composition for a plasticized vinyl chloride resin according to claim 1, wherein the aliphatic polyester is a ring-opening polymer of a lactone. 4. An ethylene-vinyl alcohol copolymer resin comprising the lactones 5 to 50 in the presence of 95 to 50% by weight of the ethylene-vinyl alcohol copolymer according to claim 2.
The coating composition for a plasticized vinyl chloride-based resin according to any one of claims 1 to 3, wherein the coating composition is obtained by ring-opening polymerization of wt% (the sum of both is 100 wt%). 5. A lactone wherein ε-caprolactone or δ
The coating composition for a plasticized vinyl chloride resin according to claim 3 or 4, which is valerolactone. 6. A molded article of a plasticized vinyl chloride resin, the surface of which is coated with the coating composition for a plasticized vinyl chloride resin according to claim 1.