JP2001354818A - Non-yellowing plastisol composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastisol composition having an excellent adhesive property and storing stability free from yellowing of a paint film. SOLUTION: This plastisol composition used for a sealing of an automobile body, an undercoat of a chipping resistant paint includes a homopolymer and/or a copolymer of vinyl chloride and a tackifier which is a polyfunctional block urethane prepolymer including three or more blocked isocyanate groups in a molecule.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastisol composition used for a sealing composition of an automobile body, an anti-chipping paint and the like.

[0002]

BACKGROUND OF THE INVENTION Conventionally, a sealing composition for an automobile body,
In coating plastisol compositions such as undercoats of chipping-resistant paints, it is common to add an adhesion-imparting agent for the purpose of imparting adhesion to the cationic electrodeposition coating surface, Various ideas have been devised.

For example, JP-A-57-105441 describes an isocyanate polymer obtained by trimerizing tolylene diisocyanate or diphenylmethane diisocyanate. JP-A-62-41278 proposes to add a long-chain alkyl (having 3 or more carbon atoms) phenol block of an aromatic diisocyanate polymer. JP-A-57-105441 discloses a lactam-blocked polyisocyanate disclosed in JP-A-1-170633.
In the above publication, it is proposed to use an isocyanurate type blocked urethane polymer in combination with an active amino group-containing polyamide compound.

[0004]

When the aromatic isocyanate or the aromatic polyisocyanate is used, a problem such as yellowing of the plastisol and the top coat always occurs due to temperature, humidity, light and the like.

[0005] Aliphatics which are non-yellowing isocyanates,
When an alicyclic isocyanate is used, the adhesiveness which is the original purpose does not appear, and a method of adding a block dissociation accelerator such as mono- or polyamide has been adopted.
No yellowing occurred due to humidity, light, etc., and none of them satisfied the adhesiveness, storage stability, and yellowing of the coating film.

[0006] Under various conditions, for example, various compounding agents can be used. Even in a high-temperature and high-humidity atmosphere, there is no deterioration in performance, and no bubbles or yellowing occurs, and stable processing can be performed.
Moreover, the present inventors have made intensive studies to develop a plastisol composition having a high adhesive strength.

As a result, it has been found that the above object can be achieved by adding a specific diisocyanate prepolymer block as an adhesion-imparting agent to a plastisol, thereby completing the present invention.

[0008] That is, an object of the present invention is to provide a plastisol composition free from a decrease in adhesive strength and a yellowing of a coating film even when processed under various conditions such as high temperature, high humidity and light.

[0009]

According to the present invention, there is provided a plastisol composition containing a homopolymer and / or copolymer of vinyl chloride and an adhesion-imparting agent, wherein the adhesion-imparting agent is at least 3 per molecule. It is a plastisol composition comprising a polyfunctional blocked urethane prepolymer containing two blocked isocyanate groups.

The adhesion-imparting agent contained in the plastisol composition may be a mixture of a polyfunctional block urethane prepolymer containing at least three blocked isocyanate groups in one molecule and a crosslinking component.

A part or all of the vinyl chloride copolymer contained in the plastisol composition may be a vinyl chloride copolymer obtained by copolymerizing a monomer containing a hydroxyl group or a carboxyl group with a vinyl chloride monomer.

[0012] The polyfunctional block urethane prepolymer containing at least three blocked isocyanate groups in one molecule contained in the plastisol composition is composed of an aliphatic or alicyclic diisocyanate compound and at least three polyisocyanate groups in one molecule. Is a compound obtained by reacting a (poly) hydroxy compound having a hydroxyl group with a blocking agent having active hydrogen.

[0013] The crosslinking component contained in the plastisol composition is a (poly) hydroxy compound having at least two hydroxyl groups in one molecule.

The blocking agent having an active hydrogen used for forming the adhesion-imparting agent in the plastisol composition is an alkylphenol, an oxime compound or a lactam compound.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The vinyl chloride homopolymer and / or copolymer used for forming the above-mentioned plastisol composition comprises a vinyl chloride monomer homopolymer, a vinyl chloride monomer and a copolymerizable monomer. It is a copolymer, and its copolymerizable monomer includes vinyl esters such as vinyl acetate, vinyl propionate and vinyl stearate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (Meth) acrylates such as -hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate, and carboxylic acids having an unsaturated group such as (meth) acrylic acid and maleic acid, diethylmalate, and dibutylma Such as maleate, diethyl fumarate, dibutyl fumarate, etc. Fumaric acid esters, vinyl ethers such as vinyl methyl ether and vinyl butyl ether and the like, the degree of polymerization, for example, from 500 to 200
It is about 0.

In the vinyl chloride homopolymer and / or copolymer used for forming the above plastisol composition, vinyl chloride homopolymer and / or vinyl chloride copolymer 100 containing no hydroxyl group or carboxyl group It is preferable that the amount of the vinyl chloride copolymer containing a hydroxyl group or carboxyl group is in the range of 1 to 100 parts by weight, preferably 10 to 60 parts by weight with respect to parts by weight.

The adhesion-imparting agent used for forming the above-mentioned plastisol composition includes an aliphatic or alicyclic diisocyanate, a (poly) hydroxy compound having at least three hydroxyl groups in one molecule, and a blocking agent having active hydrogen. A polyfunctional block urethane prepolymer having at least three blocked isocyanate groups in one molecule, obtained by reacting the agent, or a cross-linking component having at least two hydroxyl groups in one molecule It is a mixture with a (poly) hydroxy compound.

The above-mentioned polyfunctional block urethane prepolymer is prepared by mixing an aliphatic or alicyclic diisocyanate and a (poly) hydroxy compound having at least three hydroxyl groups in one molecule at 50 to 150 ° C. in a nitrogen stream. It is obtained by reacting and synthesizing a urethane prepolymer and blocking the remaining isocyanate groups with a blocking agent having active hydrogen, and having a number average molecular weight in the range of 500 to 6000, particularly in the range of 2500 to 5500. Is preferred.

Examples of the aliphatic or alicyclic diisocyanate constituting the polyfunctional block urethane prepolymer include hexamethylene diisocyanate (HD
I), pentamethylene-1,5-diisocyanate,
Examples include 2,2,4-trimethyl-hexamethylene-1,6-diisocyanate (TMDI), lysine diisocyanate, isophorone diisocyanate (IPDI), norbornene diisocyanate, and the like. You may.

Examples of the polyfunctional block urethane prepolymer and the (poly) hydroxy compound having at least two hydroxyl groups in one molecule which constitute the crosslinking agent component include 1,3-butanediol and 1,3-butanediol. 4-butanediol, neopentyl glycol, 1,6-hexanediol, glycerin, trimethylolpropane, ぺ triol, pentaerythritol, diglycerin, ditrimethylpropane, dipentaerythritol, sorbitol, xylitol, galactitol, glucose, galactose, Mannose, sucrose, maltose, raffinose, stachyose and the like. Further, polyether polyols which are alkylene oxide adducts of the above (poly) hydroxy compounds such as ethylene oxide, propylene oxide and butylene oxide can also be used.

As the blocking agent constituting the block urethane prepolymer, phenols, oximes, lactams, dialkylamines, active methylene compounds and pyrazoles can be used. Among them, alkylphenols, oximes, and lactams having an alkyl group having 3 or more carbon atoms as a substituent are particularly preferable, and two or more of these can be used in combination.

The phenols include those having 3 carbon atoms.
Alkylphenols having at least two alkyl groups as substituents, propylphenol and its isomers,
Examples thereof include butylphenol and its isomers, octylphenol and its isomers, and nonylphenol and its isomers. Two or more of these can be used in combination. Further, in addition to alkylphenols, phenol, cresol, nitrophenol, chlorophenol or isomers thereof may be used in combination.

The oximes include acetoxime and methyl ethyl ketoxime, and the lactams include γ-butyrolactam, β-propiolactam and ε-
Examples of the dialkylamines such as caprolactam include:
Dibutylamine, diisopropylamine, di-tert
Examples of the active methylene compound such as -butylamine, di-2-ethylhexylamine and the like include malonic acid, diethyl acetoacetate, acetylacetone and the like and the pyrazoles, and two or more of these can be used in combination.

In the present invention, the amount of the adhesion-imparting agent added to the plastisol composition is from 0.3 to 30 parts by weight in terms of solid content based on 100 parts by weight of the homopolymer and / or copolymer of vinyl chloride. Parts, preferably 0.5 to
The range is 5 parts by weight.

The above plastisol composition contains a plasticizer,
Fillers are added. The plasticizer used for forming the above plastisol composition can be used as long as it is generally used for this kind of purpose.

For example, di-n-octyl-phthalate,
Phthalate plasticizers such as di-2-ethylhexyl-phthalate (DOP), diisononyl phthalate (DINP), diheptyl phthalate (DHP), di-2-ethylhexyl adipate (DOA), di-2-ethylhexyl azelate, sebacine Fatty acid ester-based plasticizers such as di-2-ethylhexyl acid, and the like, which are appropriately selected depending on required properties such as stability, curability, hardness after curing, heat resistance, viscosity and compatibility of the plastisol. These can be used even if they are mixed at an arbitrary ratio.

The filler used for forming the above plastisol composition includes calcium carbonate, kaolin, diatomaceous earth, talc, magnesium oxide, calcium oxide,
Barium oleate, etc. can be used. Collected waste paint or recycled paint fine powder is used as part of the filler from the viewpoint of resource recycling, and glass balloons and shirasu are used as part of the filler from the viewpoint of reducing the weight of plastisols. Hollow bodies such as balloons and plastic balloons can also be used.

In the above plastisol composition, in addition to the above-mentioned components, additives such as a thickener, a stabilizer, an adsorbent, a dispersant, a leveling agent, an antifoaming agent and a block dissociation accelerator can be used. .

As a more specific example of the above plastisol composition, the following may be mentioned. In a plastisol composition containing a homopolymer and / or copolymer of vinyl chloride, an adhesion promoter, a plasticizer and a filler, the homopolymer and / or copolymer of vinyl chloride contains a hydroxyl group or a carboxyl group. A vinyl chloride copolymer obtained by copolymerizing a monomer and a vinyl chloride monomer, wherein the adhesiveness-imparting agent comprises an aliphatic or alicyclic diisocyanate and a (poly) hydroxy compound having at least three hydroxyl groups in one molecule; It comprises a polyfunctional blocked urethane prepolymer having at least three blocked isocyanate groups in one molecule, obtained by reacting a blocking agent having active hydrogen, and a crosslinking component.

The above plastisol composition is prepared by dispersing and kneading a homopolymer and / or copolymer of vinyl chloride, an adhesion-imparting agent, a plasticizer, a filler and, if necessary, other additives. And then uniformly kneaded, followed by defoaming under reduced pressure to produce.

The above-mentioned plastisol composition has excellent adhesiveness to a metal-coated surface, especially a cationic electrodeposition coated surface, by heat treatment at a relatively low temperature and for a short time. It is particularly suitable as a sealing composition for the purpose of buffering stepping stones and sealing pinholes, and as an undercoat for chipping-resistant paints. In addition, it can be applied to various industrial uses such as adhesives, sealing agents, coating agents and paints.

The method for coating the plastisol composition is as follows:
It is appropriately selected depending on the use, and for example, pouring, dipping, spray coating, brush coating and the like are general. Conventional plastisol compositions applied to adherends are typically 140
Although the composition is cured by a heat treatment at a temperature of up to 160 ° C., the plastisol composition of the present invention can obtain good adhesion even at a heat treatment at a low temperature of 120 ° C., and the overcoated paint does not turn yellow.

[0033]

Next, the plastisol composition of the present invention will be described in detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples unless it exceeds the gist. Parts and% in Examples and Comparative Examples are parts by weight and% by weight, unless otherwise specified.

1) Production of plastisol composition According to the composition shown in Table 1, Zeon 121 (manufactured by Zeon Corporation) as a vinyl chloride homopolymer, and P-100 (Mitsubishi Chemical Corporation) as a vinyl chloride copolymer. Made),
Zeon 37J (manufactured by Nippon Zeon Co., Ltd.), diisononyl phthalate (DINP) as a plasticizer, calcium carbonate as a filler, lead sulfate (PbSO ₄ ) as a stabilizer, and a block of the following synthesis examples and comparative synthesis examples as an adhesion promoter. An isocyanate prepolymer and a (poly) hydroxy compound as a crosslinking component were charged in a kneader, kneaded for 30 minutes, and then defoamed to produce a plastisol composition.

2) Evaluation Test The evaluation of the plastisol composition was performed by the following test. Storage stability test of plastisol composition Using a BH-type viscometer, the plastisol composition at 40 ° C ×
The viscosity at 25 ° C. before and after storage was measured for 10 days, and the thickening rate was calculated. And the case where the thickening rate was less than 30% was set as pass (o), and the case where it was 30% or more was rejected (x).

Tensile shear bond strength test A metal plate coated with a cation electrodeposition coating was coated with a test specimen of 25.4 mm.
× 90 mm, and the test piece was coated with the plastisol compositions of Examples and Comparative Examples in a thickness of 1.0 mm and 25.4 mm × 2.
After applying to an area of 5.4 mm, 120 ° C. × 30 min
And the tensile shear adhesive strength of the coating film was measured according to JIS K-6830.

The state of the shear surface was visually observed, and the case of cohesive failure was (cf) and the case of interfacial failure was (af).

Yellowing Test of Coating Film Using a cationic electrodeposition coated plate as an adherend, the coating of the plastisol composition was applied to a thickness of 5 mm.
After a heat treatment at 40 ° C. × 10 min, a topcoat paint Super White 326 (manufactured by Kansai Paint Co., Ltd.) having a thickness of 5 μm
m, and then heat-treated at 140 ° C. for 20 minutes to obtain a test piece, which was measured with a fade meter for 200 hours.
The discoloration after rs exposure was visually inspected, and the case where coloring was confirmed was evaluated as (x).

3) Synthesis of adhesion-imparting agent Comparative Synthesis Example-1 Trimer of hexamethylene diisocyanate (HDI nullate) was placed in a flask equipped with a stirrer, thermometer and nitrogen inlet tube.
168 parts and 1496 parts of dioctyl phthalate (DOP) are charged, and then paraoctyl phenol (POP) 2
06 parts and 0.3 parts of dibutyltin dilaurate were added thereto, and reacted in a temperature range of 50 to 80 ° C. under a nitrogen stream to obtain an isocyanate group absorption in an infrared absorption spectrum of 2260 cm ^−1.
The reaction was continued until there was no more, to prepare a 20% solution of an alkylphenol block of a hexamethylene diisocyanate polymer in dioctyl phthalate.

Comparative Synthesis Example 2 The same procedure was followed except that hexamethylene diisocyanate trimer (HDI nullate) in Comparative Example 1 was replaced with 174 parts of tolylene diisocyanate trimer (TDI nullate). A 20% dioctyl phthalate solution of an alkylphenol block of an isocyanate polymer was prepared.

Synthesis Example 1 (Synthesis of 4-functional block urethane prepolymer) In a flask equipped with a stirrer, a thermometer and a nitrogen inlet tube, 100.8 parts of hexamethylene diisocyanate (HDI) and 26.8 parts of trimethylolpropane (TMP) were added. And 10.4 parts of neopentyl glycol and dioctyl phthalate (D
OP) 289.7 parts were added, 0.3 part of dibutyltin dilaurate was added, and the mixture was reacted in a temperature range of 50 to 80 ° C under a nitrogen stream to synthesize a tetrafunctional urethane prepolymer.
Then, 48.1 parts of tert-butylphenol and 7.0 parts of methyl ethyl ketoxime are added as blocking agents, and the mixture is reacted at the same temperature until the absorption at 2260 cm ⁻¹ of isocyanate group in the infrared absorption spectrum disappears, and the tetrafunctional block urethane prepolymer is added. A 40% dioctyl phthalate solution was prepared.

Synthesis Example-2 (Synthesis of Hexafunctional Block Urethane Prepolymer) In a flask equipped with a stirrer, thermometer and nitrogen inlet tube, 201.6 parts of hexamethylene diisocyanate (HDI), 53.6 parts of trimethylolpropane, and neopentyl 31.2 parts of glycol and 553.3 parts of dioctyl phthalate were charged, and 0.3 part of dibutyltin dilaurate was added and reacted in a range of 50 to 80 ° C. under a nitrogen stream to synthesize a hexafunctional urethane prepolymer.

Next, 72.1 parts of tert-butylphenol (PTBP) and 10.4 parts of methyl ethyl ketoxime were added as a blocking agent, and the mixture was reacted at the same temperature until the peak at 2260 cm ^-1 of isocyanate group absorption in the infrared absorption spectrum disappeared. A 40% dioctyl phthalate solution of a hexafunctional block urethane prepolymer was prepared.

Synthesis Example 3 (Synthesis of 9-Functional Block Urethane Prepolymer) In a flask equipped with a stirrer, a thermometer, and a nitrogen inlet tube, 352.8 parts of hexamethylene diisocyanate (HDI), 93.8 parts of trimethylolpropane, and neopentyl 62.4 parts of glycol and dioctyl phthalate (DOP) 94
9.2 parts were charged, and 0.3 parts of dibutyltin dilaurate was added, and reacted in a temperature range of 50 to 80 ° C under a nitrogen stream,
A 9-functional urethane prepolymer was synthesized. Next, tert-butylphenol (PTBP) is used as a blocking agent.
108.1 parts and methyl ethyl ketoxime 15.7 parts were added and reacted at the same temperature until the peak at 2260 cm ^-1 of the isocyanate group absorption in the infrared absorption spectrum disappeared, thereby producing a 40% dioctyl phthalate solution of a 9-functional block urethane prepolymer. did.

[0045]

[Table 1]

According to the experimental results in Table 1, the plastisol composition of the present invention has excellent adhesiveness and storage stability,
There was no yellowing of the coating film, indicating that all were satisfactory.

[0047]

The plastisol composition of the present invention has excellent adhesiveness to a cationic electrodeposition coated surface in a relatively low temperature, short-time heat treatment and in a low addition region of an adhesion imparting agent,
Further, it has storage stability and does not yellow even in a coating film.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09K 3/10 C09K 3/10 D (C08L 27/06 (C08L 27/06 75:04) 75:04) (C08F 214/06 (C08F 214/06 218: 04 218: 04 220: 18 220: 18 222: 10 222: 10 216: 12) 216: 12) (72) Inventor Osamu Mizobuchi Nishi-kujo-cho, Nara City, Nara Prefecture 5-chome No. 2 2 Kyoeisha Chemical Co., Ltd. Nara Research Laboratory F-term (reference) 4H017 AA04 AA31 AA39 AB03 AB10 AC16 AC17 4J002 BD041 BD081 BD091 CK022 EC046 EJ036 ES016 FD146 FD202 HA08 4J034 HA07 HC03 HC17 HC22 HC46 HC52 HC04 HD73 HD73 MA22 RA07 RA08 RA12 4J038 CD021 CD031 DG302 GA03 GA06 JA20 JA21 KA03 NA03 NA12 PA07 PB07 PC02 4J100 AC03P AE03Q AG02Q AG04Q AL03Q AL09Q AL80Q CA04

Claims (6)

[Claims] 1. A plastisol composition containing a homopolymer and / or copolymer of vinyl chloride and an adhesion-imparting agent, wherein the adhesion-imparting agent contains at least three blocked isocyanate groups in one molecule. A plastisol composition comprising a polyfunctional block urethane prepolymer. 2. The plastisol composition according to claim 1, wherein a crosslinking component is added to the adhesion-imparting agent. 3. The vinyl chloride copolymer according to claim 1, wherein a part or all of the vinyl chloride copolymer is a vinyl chloride copolymer obtained by copolymerizing a monomer containing a hydroxyl group or a carboxyl group with a vinyl chloride monomer. Item 3. A plastisol composition according to Item 2. 4. The polyfunctional block urethane prepolymer containing at least three blocked isocyanate groups in one molecule has an aliphatic or alicyclic diisocyanate compound and at least three hydroxyl groups in one molecule (poly 4. The plastisol composition according to claim 1, which is a compound obtained by reacting a hydroxy compound with a blocking agent having active hydrogen. 5. The plastisol composition according to claim 2, wherein the crosslinking component is a (poly) hydroxy compound having at least two hydroxyl groups in one molecule. 6. The plastisol composition according to claim 4, wherein the blocking agent having active hydrogen is an alkylphenol, oxime or lactam.