JPH02147652A - Plastisol composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which can firmly bond to a thick, cationically electrodeposited surface by a relatively low-temperature and short- time treatment and has excellent storage stability by using a vinyl chloride polymer as a base and adding a specified tackifier to the base. CONSTITUTION:A plastisol composition comprising a vinyl chloride polymer, a plasticizer, a tackifier and a thermal cleavage accelerator, wherein the tackifier is an allyl compound-blocked cyanurate ring-containing aromatic diisocyanate polymer (e.g. trimethylolpropane diallyl ether-blocked cyanurate ring-containing tolylene diisocyanate polymer). A plastisol composition which can firmly bond to a metallic coated surface, particularly a cationically electrodeposited surface, more particularly thick, cationically electrodeposited surface by a relatively low-temperature and short-time heat treatment and has excellent stability can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to adhesives in various industries including the automobile industry.
This invention relates to plastisol compositions that are most suitable for applications such as sealants and coating agents.

[Conventional technology]

It is well known that plastisol compositions have been used to protect various substrates, particularly for coating metal surfaces, for purposes such as rust prevention. In recent years, focusing on the automobile industry,
The undercoat coating has been changed from the conventional anionic electrodeposition coating to cationic electrodeposition coating, which has excellent corrosion resistance, and the coating film is becoming thicker year by year. Accordingly, there is a strong demand for plastisol compositions that have sufficient adhesion to cationic electrodeposited surfaces, can be fired by heating at relatively low temperatures for a short period of time, and have excellent storage stability.

Conventionally, in order to improve the adhesion of plastisol,
A method using urethane has been proposed. For example, (1
) JP-A No. 57-105441 discloses a method using an aromatic diisocyphate polymer (incyanurate compound containing a sardine group); (2) JP-A No. 55-11894;
No. 8, JP-A No. 59-120651 describes a method of using polyols, a block of urethane prepolymer from an organic diisocyanate, and a mono- or polyamide compound containing an active amino group as adhesion imparting agents; No. 62-41278 discloses a method using a long-chain alkylphenol block of an aromatic diisocyphate polymer.

[Problem to be solved by the invention]

Among these methods, method (1) has high reactivity because it has a free incyanate group (NGO) at the end, and the storage stability of the plastisol composition is affected by trace amounts of moisture in the air or in the plastisol. is not sufficient. In the case of (2), there are disadvantages such as discoloration caused by heat or light, and insufficient storage stability. Also (3
), sufficiently satisfactory adhesion cannot be obtained, and the lack of adhesion is particularly remarkable for thick-film cationic electrodeposition coated steel sheets.

Therefore, the object of the present invention is to improve these conventional drawbacks, and to provide a film that can be firmly adhered to metal coated surfaces, especially cationic electrodeposition coated surfaces, and is storage stable, by heat treatment at a relatively low temperature and in a short time. The object of the present invention is to provide a plastisol composition with excellent properties.

[Means to solve the problem]

As a result of intensive research into plastisol compositions, the present inventors have found that the above object can be achieved by using a block of an aromatic diisocyanate polymer having a cyanurate ring as an adhesion imparting agent. Ta.

That is, the present invention provides a plastisol composition containing a vinyl chloride polymer, a plasticizer, an adhesion promoter, and a thermal cleavage accelerator, in which an allyl compound block of an aromatic diisocyanate polymer having a cyanurate ring is used as an adhesion promoter. This is a plastisol composition using the human body.

To explain in more detail, the vinyl chloride polymer used in the plastisol composition of the present invention is a homopolymer of vinyl chloride or a copolymer of a monomer copolymerizable with vinyl chloride; Or they can be used in combination.

Examples of the seven polymers copolymerizable with vinyl chloride include vinyl esters such as vinyl acetate, vinyl propionate, and vinyl stearate; methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate; (Meth)acrylic esters such as 2-hydroxyethyl/L/(meth)acrylate and 2-hydroxypropyl (meth)acrylate; Maleic acid esters of diethyl maleate and digityl maleate (1); diethyl fumarate, zig Fumaric acid esters such as til fumarate; vinyl ethers such as vinyl methyl ether and vinyl butyl ether! Examples include the top.

The degree of polymerization of vinyl chloride polymer is 500 to 2000
You can use any one that is normally commercially available. For example, commercially available products include Zeon 121, Zeon 37J (manufactured by Nippon Zeon Co., Ltd.), Kanevinyl PSL-10
, Rikibini/L' PSM-80, Kanebini) V PC
B-12 (manufactured by Kanekabuchi Chemical Industry Co., Ltd.), Denkavinyl PA-
1000, Denkabinir ME-xso (manufactured by Kikagaku Kogyo Co., Ltd.), and the like. These vinyl chloride polymers can be used alone or in a mixture of two or more.

As the plasticizer used in the present invention, any plasticizer that is generally used for this purpose is effective and is not particularly limited, but for example, di-n-octyl phthalate (DOP
), di-2-ethylhexyl phthalate, diisononyl phthalate (DINP), digtylphumarate (DH
Phthalic acid plasticizers such as P ); di-2-ethylhexyl adipate (DOA) azelaic acid di-2
- Fatty acid ester plasticizers such as ethylhexyl and di-2-ethylhexyl sebacate, etc., and are selected as appropriate depending on the required performance such as plastisol stability, curability, hardness after curing, heat resistance, cold resistance, and compatibility. These can be used alone or in combination of two or more. The amount of plasticizer used is generally 30 to 300 parts by weight, preferably 100 to 200 parts by weight, per 2 parts of 100 parts Lλ of the vinyl chloride polymer.

Further, a part of the plasticizer can be replaced with a solvent such as dodecylbenzene or mineral turpentine, which can be selected depending on the purpose.

The adhesion-imparting agent used in the present invention imparts adhesion to the plastisol composition, and is an allyl compound block of an aromatic diisocy7-monomer having an isocyanurate ring.

The aromatic diisocyanate 4-H constituting the above-mentioned aromatic diisocyanate polymer having an isocyanurate ring includes, for example, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, etc., which may be used alone or in a mixture in any proportion. Alternatively, a part thereof may be replaced with an aliphatic diisocyanate such as hexamethylene diisocyanate, or an alicyclic diisocyanate such as isophone diisocyanate.

The above-mentioned aromatic diisocyanate polymer is preferably synthesized in a plasticizer used in the target plastisol composition, and an inert solvent such as ethyl acetate or butyl acetate may also be used depending on the case.

Examples of the polymerization catalyst include Mannich base and alkali metal salts of fatty acids, which can be obtained by known polymerization methods.

Next, the remaining incyanate groups of the obtained aromatic diisosyphate polymer having a cyanurate ring are blocked with an allyl compound to produce a block product. Examples of allyl compounds used for blocking include alcohols such as allyl alcohol and allyl carbinol;
Ethylene glycol monoallyl ether, diethylene glycol monoallyl ether, glycerin monoallyl ether, glycerin diallyl ether, trimethylolpropane monoallyl ether, trinotyrolpropane diallyl ether, pentaerythritol triallyl ether, allyl glycidyl ether, diglycerol diallyl ether, etc. Ethers; amines such as allylamine and diallylamine, monoallylphenol (0
-pm-+p-allylphenol), 2-allyl-6-
Examples include phenols such as methylphenol. These may be used alone or in combination of two or more.

Furthermore, blocks of diisocyanate polymers other than the allyl compound blocks mentioned above, such as known alkylphenol blocks and blocks of oximes, may be used in combination, if desired.

The thermal decomposition accelerator used in the plastisol composition Q of the present invention is the one used to dissociate the allyl compound block of the aromatic diisocyanate polymer having an incyanurate ring used as an adhesion imparting agent. Examples thereof include sodium and potassium salts of alkyl sulfuric acids and alkylphosphonic acids, and metal salts of fatty acids having 8 to 20 carbon atoms such as sodium, potassium, and zinc. Further examples include tin compounds such as diptyltin dilaurate, dioctyltin maleate, digtyldibutoxytin, and bis(2-ethylhexyl)tin oxide. One or more of these may be used. In the present invention, tin compounds are most preferred. The amount used is not particularly limited, but is generally in the range of 0.01 to 5 parts by weight, preferably 0.1 to 2 parts by weight, per 100 parts by weight of the vinyl chloride polymer.

In addition to the above-mentioned components, other additives such as fillers, thickeners, stabilizers, adsorbents, etc. can be added to the plastisol composition of the present invention. Although these additives are not limited, examples of fillers include kaolin, diatomaceous earth, calcium carbonate, talc, etc., and examples of thickeners include bentonite, anhydrous silica, metal soap, etc. Metal soaps are also used as stabilizers, such as zinc stearate, calcium stearate, barium oleate, etc., and can be used alone or as a combined stabilizer. Adsorbents are also used to remove water from plastisol, such as magnesium oxide,
Add powder such as calcium oxide.

To produce the plastisol composition of the present invention, the vinyl chloride polymer, a plasticizer, the present invention (adhesion imparting agent, thermal cleavage accelerator, and other additives as required) are uniformly kneaded, Finish by defoaming.

The plastisol composition of the present invention is used as a sealant, coating, and adhesive for protecting substrates in various industries including the automobile industry. In particular, it can be used for purposes such as rust prevention on car bodies coated with cationic electrodeposition in the automobile industry, buffering of flying stones during driving, and sealing of pinholes. The plastisol composition according to the present invention is applied to the body of a vehicle, and the cured coating film provides excellent performance such as chipping resistance, adhesion, impact resistance, cold resistance, bendability, and corrosion resistance.

When applying the plastisol composition of the present invention, 1. Airless spray, hot air spray, 1. balding, dipping,
Painting methods such as pouring can be used, and normal methods can be used depending on the purpose and application.

The coating film thickness of the plastisol composition of the present invention is usually 0.1 to
5 Apply to the temperature of 100 to 170℃.
It can be cured by baking for 10 to 40 minutes at a temperature of .

[For production]

Since the plastisol composition according to the present invention contains an allyl compound block of an aromatic diiso or sifted polymer having a cyanurate ring as an adhesion imparting agent, the coating film formed can be applied to a metal-coated surface, especially a cationic one. Strongly adheres to electrodeposition coated surfaces (thick cationic electrodeposition coated surfaces). Furthermore, the plastisol of the present invention is easy to handle, has good storage stability, and does not exhibit an extreme increase in viscosity even when left for a long time. In addition, the plastisol composition of the present invention contains a floc of an aromatic diisosyphte polymer having a cyanurate ring as an adhesion imparting agent, and an allyl compound is used as a blocking agent. There is no coloration during processing or after application, and it has good adhesion not only to cationic electrodeposited surfaces but also to top coats such as alkyd resins, epoxy resins, and acrylic resins, and even when top coats are applied thinly. It has the advantage of not having to worry about discoloration.

〔Example〕

Hereinafter, the effects of the present invention will be specifically illustrated using Examples and Comparative Examples. The parts and percentages in the text below are parts by weight and percentages by weight unless otherwise specified.

Reference Example: Preparation of allyl compound block of aromatic diisocyanate polymer having cyanurate ring In a flask 11 equipped with a stirrer, thermometer, and nitrogen inlet tube, 113 parts of tolylene diisocyanate, 715 parts of dioctyl phthalate, and sheaslate were added. 0.5 part of potassium caprylate was added as a reaction catalyst, and the mixture was heated and stirred at 25 to 60°C under a nitrogen stream to react until the isocyanate content reached 4.3% to obtain a tolylene diisocyanate polymer (cyanurate). Ta.

Next, trimethylolpropane diallyl ether 125
The addition reaction was carried out under a nitrogen stream at an internal temperature of 70°C.

The reaction was carried out until the absorption of the NGO group of IRG Trowel 2260α-1 disappeared to obtain a dioctyl phthalate solution containing 25% of a trinotylol propane diallyl ether block of a tolylene diisocyanate polymer having a cyanurate ring. This is referred to as adhesion-imparting agent A.

Using the above-mentioned production method, a solution containing 25% allyl compound blocks of tolylene diisocyanate polymer having cyanurate rings was obtained using each of the allyl compounds shown in Table 1 below, and these were used as an adhesive agent. B-H.

Table 1 Comparative Reference Example Following the production example of the reference example above, monoalkylphenol blocks 1 to K of tolylene diisocyanate polymers shown in Table 2 below were prepared using the monoalkylphenol blocking agents shown in Table 2 below. .

Examples 1 to 8 Production of plastisol composition Vinyl chloride polymer Zeon 121 20 manufactured by Nippon Zeon Co., Ltd.
parts, Zeon 37J 80 parts, dioctyl phthalate (
DOP) 150 parts, calcium carbonate 150 parts, stabilizer (
Plastisol composition 1 was prepared by kneading 5 parts of Pb5O, ), 28 parts of the adhesion promoter A, and 2 parts of the thermal cleavage accelerator diptyltin laurate using a kneader at room temperature for 30 minutes and defoaming.

Separately, plastisol compositions 2 to 8 were prepared using the same amounts of adhesion promoters B-H.

Comparative Examples 1 to 3 Adhesion improver A of the above example was prepared in the same manner as in the above example.
Plastisol composition comparative examples 1 to 3 were prepared by using the same amounts of the adhesion promoters 1 to K instead of the above.

Test Examples The plastisol compositions, Examples 1-8 and Comparative Examples 1-
Evaluation of No. 3 was conducted as follows.

(1) Storage stability test of plastisol composition The viscosity of the produced plastisol composition at 20° C. was measured using a Brookfield BH viscometer, and this was taken as the initial viscosity.

Next, put the plastisol composition in a glass container and
The viscosity of the sample was measured in the same manner after the sample was left in a constant temperature bath at 1° C. for 7 days, and its thickening rate was determined.

(2) Shear strength test Shear strength was measured according to JISK-6830 (automobile sealant test method) using a test piece of a steel plate with a coating film formed by cationic electrodeposition as an adherend. however,
The thickness of the plastisol coating is 0.2 mm,
The heat treatment was carried out at 120℃ for 30 minutes, and the tensile rate was 25 mm/cm.
I went in minutes.

(3) Condition of shear plane This was determined visually.

(4) Discoloration test of paint film A steel plate with a paint film formed by cationic electrodeposition was used as the adherend, and a paint film of plastisol composition was applied to a thickness of 5 nm, and heat treated at 140°C for 10 minutes. After that, a topcoat paint (product name: Nuber White 326 manufactured by Kansai Paint Co., Ltd.) was applied to a film thickness of 5 μm, and then 1
A test piece was heat-treated at 40°C for 20 minutes and examined for discoloration after being exposed for 240 hours using a fade-o-meter.

The test results are shown in Table 3.

〔Effect of the invention〕

From the data of the above test examples, it can be seen that the plastisol composition according to the present invention exhibits excellent adhesiveness (shear strength). Furthermore, like conventional plastisol compositions, it has excellent storage stability, and no extreme increase in viscosity is observed even when left for a long time.

Furthermore, the gray color of the paint film during processing and the discoloration of the top coat film are comparable to, or even better than, conventional ones.

Claims (1)

[Claims] 1. In a plastisol composition containing a vinyl chloride polymer, a plasticizer, an adhesion promoter, and a thermal cleavage accelerator, the adhesion promoter is a block of an allyl compound of an aromatic diisocyanate polymer having a cyanurate ring. A plastisol composition comprising: