JPH0613633B2 - Plastisol composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plastisol composition. More specifically, it relates to a plastisol composition most suitable for applications such as adhesives, sealing agents and coating agents in various industries including the automobile industry.

[Prior Art] It is known to add an organic polyisocyanate compound to a plastisol composition as a method for improving the adhesiveness of the plastisol.

For example, JP-A-57-105441 describes adding tolylene diisocyanate or an isocyanate polymer obtained by trimerizing diphenylmethane diisocyanate (cyanurate) to plastisol. In JP-A-59-131669, a lactam block polyisocyanate may be added, and in JP-A-62-41278 and JP-A-62-190267, long-chain alkyl (carbon) of an aromatic diisocyanate polymer is added. It is proposed to add a phenol block body (equal to or more than 4).

The plastisol composition of JP-A-57-105441 has a drawback that it has a high reactivity because it has a free isocyanate group (NCO group) at the end, has a problem of stability, and has a short shelf life. Further, in the case of using a block body, since this block agent is cleaved, when a polyamide containing an active amino group is used as a thermal cleavage accelerator, the coating film obtained therefrom undergoes thermal discoloration and has no water resistance. When the block agent is a long-chain alkylphenol, the discoloration is improved, but on the metal coated surface (cationic electrodeposition coated steel sheet surface), satisfactory adhesiveness is still obtained. Has not been done. In particular, it is remarkable on the surface of thick film cationic electrodeposition coating.

[Problems to be Solved by the Invention]

The present inventors have improved these drawbacks, firmly adhere to a cationic electrodeposition coated surface, have excellent water resistance, form a coating film without thermal discoloration, and further provide a plastisol composition having excellent storage stability. As a result of investigations for obtaining the same, the present invention has been achieved by using a monoisoprobiphenol block product of an aromatic diisocyanate polymer as an adhesiveness-imparting agent.

[Means for Solving the Problems]

The present invention is a plastisol composition comprising a vinyl chloride polymer, a plasticizer, an adhesiveness-imparting agent, and a thermal cleavage accelerator, and contains a monoisopropylphenol block of an aromatic diisocyanate polymer as an adhesiveness-imparting agent. Plastisol composition.

Explaining the present invention in detail, the vinyl chloride-based polymer used in the plastisol composition of the present invention is a homopolymer of vinyl chloride or a copolymer of vinyl chloride and a monomer which is a copolymer, and the copolymerization thereof. Possible monomers include vinyl acetate, vinyl propionate, vinyl stearate, and other vinyl esters; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2 -(Meth) acrylic acid esters such as hydroxypropyl (meth) acrylate; maleic acid esters such as diethyl maleate and dibutyl maleate; fumaric acid esters such as diethyl fumarate and dibutyl fumarate; vinyl methyl ether, vinyl Vinyl ethers such as butyl ether Etc. can be mentioned, the degree of polymerization, for example, about 500 to 2,000. Examples of commercially available vinyl chloride homopolymers or copolymers include, for example, ZEON 121, ZEON 37J (all manufactured by ZEON CORPORATION), Kanevinyl PSL-10, Kanevinyl PSH-.
10, Kanevinyl PSM-80, Kanevinyl PCH-12 (above, Kanefuchi Chemical Co., Ltd.), Denka Vinyl PA-1000,
Denka vinyl ME-180 (manufactured by Denki Kagaku Kogyo Co., Ltd.) and the like can be mentioned. These may be used as a mixture of two or more.

As the plasticizer, those generally used for this purpose are
All useful, eg di-n-octyl phthalate (DO
P), di-2-ethylhexyl phthalate, diisononyl phthalate (DINP), diheptyl phthalate (DHP) and other phthalic acid plasticizers; di-2-ethylhexyl adipate (DOA), di-2-ethylhexyl azelate, sebacic acid Fatty acid ester-based plasticizers such as di-2-ethylhexyl; phosphate ester-based plasticizers such as tributyl phosphate and tri-2-ethylhexyl phosphate, and the like. Stability of plastisol, curability, hardness after curing, It is appropriately selected depending on the required performance such as heat resistance, viscosity and compatibility, and one kind or a mixture of two or more kinds can be used. The plasticizer may be used in an amount of 30 to 300 parts by weight based on 100 parts by weight of the vinyl chloride polymer.

The adhesiveness-imparting agent used in the present invention is a monoisopropylphenol block product of a cyanurate polymerized product of an aromatic diisocyanate (hereinafter abbreviated as aromatic diisocyanate polymer) for imparting adhesiveness to plastisol. These aromatic diisocyanates (monomers) constituting the aromatic diisocyanate polymer include, for example, tolylene diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, etc., which are used alone or in a mixture at any ratio. Further, a part thereof may be replaced with an aliphatic diisocyanate such as hexamethylene diisocyanate or an alicyclic diisocyanate such as isophorone diisocyanate.

The aromatic diisocyanate polymer is preferably synthesized in the plasticizer used in the desired plastisol composition, and optionally an inert solvent such as butyl acetate can also be used. Examples of the polymerization catalyst include Mannich bases, alkali metal salts of fatty acids, etc., which can be obtained by polymerization (cyanurate) by a known method, and then blocked with monoisopropylphenol to give a monoamine of an aromatic diisocyanate polymer. An isopropyl phenol block is produced.

The blocking agent used in the present invention, monoisopropylphenol, has ortho, meta, and para isomers, and may be used alone or in a mixture, but it is preferable to use a block with an ortho or para body. good.

The addition amount of the monoisopropylphenol block of the aromatic diisocyanate polymer of the present invention is in the range of 0.5 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the vinyl chloride polymer. It is good to be in

The thermal cleavage accelerator is for cleaving a block of an aromatic diisocyanate polymer, and is a fatty acid having 8 to 20 carbon atoms such as zinc octylate, potassium laurate, barium oleate, and calcium stearate. Examples of the metal salt include a tin compound such as dibutyltin laurate, dioctyltin maleate, dibutyldibutoxytin, and bis (2-ethylhexyl) tin oxide. One or more of these compounds are appropriately used, but the tin compound is particularly preferable. The amount used is not particularly limited, but varies depending on the type. Generally, it tends to deteriorate the storage stability, so it is necessary to select an appropriate amount. The tin compound used in the present invention is 0.05 to 5 parts by weight, preferably 0.2 to 2 parts by weight, based on 100 parts by weight of the vinyl chloride polymer.

The plastisol composition of the present invention is not limited to these additives to which other additives such as fillers, thickeners, stabilizers, adsorbents and the like can be added in addition to the above components. Examples of the filler include kaolin, diatomaceous earth, talc and the like, and examples of the thickener include pentonite, anhydrous silica, metal soap and the like.
Metal soap and the like are also used as stabilizers, and examples thereof include zinc stearate, calcium stearate, and barium oleate, which can be used alone or as a composite stabilizer. Further, as the adsorbent, when water is contained in plastisol, powders of magnesium oxide, calcium oxide, silicon oxide, etc. are added and used.

The plastisol composition of the present invention is obtained by uniformly kneading a vinyl chloride polymer, a plasticizer, an adhesion improver, a thermal cleavage accelerator, and optionally other additives with a dispersion kneader, and then removing the mixture. Produce by foaming.

Since the plastisol composition of the present invention has advantages such as strong adhesion to a metal coated surface (particularly a cationic electrodeposition coated surface) and good storage stability, for example, in the automobile industry,
It is used for the purpose of rust prevention of body, buffer of flying pebbles, and stopping of pinholes.

The coating amount varies depending on the application and is not particularly limited. For example, when used as an undercoating material for a topcoating material, the coating film thickness may be 0.5 mm to 5 mm. Regarding the coating method, a usual method is appropriately selected depending on the application, and for example, casting, dipping, spray coating, brush coating and the like are common.

The plastisol composition applied to the article to be coated is conventionally heated to a temperature of 140 ° C. to 180 ° C. to thermally dissociate the block body and cure the same, but the plastisol composition of the present invention has a temperature of 120 ° C. to 140 ° C. A strong adhesive property is exhibited by heat treatment at a temperature for 15 to 30 minutes.

[Action]

Since the plastisol composition of the present invention contains a block of an aromatic diisocyanate polymer which has been blocked with monoisopropylphenol as an adhesion-imparting agent, the plastisol composition is applied at 120 ° C.
It adheres easily and firmly by heat treatment for 15 to 30 minutes in the temperature range of 40 ° C. That is, the monoisopropylphenol used in the present invention belongs to the one having a lower molecular weight among the alkylphenols, and the content of the isocyanate group in the added amount of the adhesiveness-imparting agent is large, and the block because it is an isoform. Since the agent is liable to be cleaved, it is imparted with strong adhesiveness by the above-mentioned heat treatment. Moreover, the plastisol composition of the present invention is easy to handle, has good storage stability, and can be used for a long period of time even if left untouched. It has advantages such as no increase in viscosity. Further, there is an advantage that there is no fear of discoloration even when the topcoat paint is applied thinly without being colored even during processing or by heat treatment after application.

The plastisol composition of the present invention can be applied as a sealing agent, a coating agent or an adhesive agent for protecting a substrate in various industries, but especially in the automobile industry, rust prevention of a body coated with cation electrodeposition, flying pebbles It is excellent as a paint for buffering, pinhole sealing, etc.

〔Example〕

Hereinafter, the effects of the present invention will be described with reference to Examples and Comparative Examples. In Examples and Comparative Examples, parts and% mean parts by weight and% by weight, unless otherwise specified.

Reference Example Production of Mono-Isopropylphenol Block of Tolylene Diisocyanate Polymer Stirrer, thermometer, and flask with nitrogen inlet tube 100 parts of tolylene diisocyanate, 400 parts of dioctyl phthalate, potassium caprylate as polymerization (cyanurate) catalyst 0 .6 parts were charged, and the temperature was 25 to 60 ° C under a nitrogen stream.
Was reacted until the isocyanate content reached 3.2% to give a polymer (cyanurate), and then 78.3 parts of o-isopropylphenol, 313.2 parts of dioctylphthalate and 0.3 part of dibutyltin laurate were added. , Absorption of isocyanate group (NCO group) in infrared absorption spectrum in the temperature range of 50 to 80 ° C under nitrogen stream (22
The reaction was continued until the amount of 60 cm ^-1 ) disappeared, and a dioctyl phthalate solution containing 20% of o-isopropylphenol block of the tolylene diisocyanate polymer was prepared. This was designated as an adhesiveness imparting agent A. Table 1 shows products produced by the same method using isomers of monoisopropylphenol, metaisopropylphenol and paraisopropylphenol as blocking agents.

Comparative Reference Example According to the production method of the Reference Example, the following alkylphenol was used as a blocking agent to produce a dioctylphthalate solution of a block of an aromatic diisocyanate polymer,
Adhesion imparting agents D, E and F are shown in Table 2.

Example 1 Production of plastisol composition Vinyl chloride polymer ZEON 37J (manufactured by ZEON CORPORATION) 10
A kneader was added to 0 part of 130 parts of dioctyl phthalate, 200 parts of calcium carbonate, 5 parts of a stabilizer (PbSO ₄ ), 28 parts of the adhesion promoter A obtained in Reference Example and 2 parts of a thermal cleavage accelerator (dibutyltin laurate). Then, the plastisol composition 1 was manufactured by kneading and defoaming at room temperature for 30 minutes.

Example 2 The vinyl chloride polymer used in Example 1 was used as Zeon 37J8.
Plastisol composition 2 was produced in the same manner as in Example 1 except that a mixture of 0 part and 20 parts of ZEON 121 (manufactured by Zeon Corporation) was used.

Examples 3 to 4 100 parts of the polyvinyl chloride polymer mixture of Example 2 and the adhesiveness-imparting agent A of Example 1 were replaced with the adhesion-imparting agent of Table 1 using the method of Example 1 above. Plastisol compositions 3 to 4 were produced using the same amounts of B to C.

Comparative Examples 1 to 3 Instead of the adhesiveness-imparting agent A in Example 2, the same amounts of the adhesiveness-imparting agents D to F of Comparative Reference Example of Table 2 above were used, and Plastisol composition Comparative Examples 1 to 3 were obtained. Manufactured.

The above-mentioned Examples 1 to 4 and Comparative Examples 1 to 3 of the plastisol composition were evaluated by the following tests.

(1) Storage stability test of plastisol composition The prepared plastisol composition was measured for its viscosity at a temperature of 20 ° C. using a Brutzfield BH viscometer, and this was taken as the initial viscosity, and then plastisol was placed in a glass container. The viscosity was measured in the same manner after the composition was placed and allowed to stand in a constant temperature bath of 40 ° C. ± 1 ° C. for 7 days, and the viscosity increase rate was determined.

(2) Tensile shear strength test The shear strength was measured according to JIS K-6830 (Testing method for automobile sealing materials) using a cationic electrodeposition coated plate as an adherend (however, the thickness of the coating film by plastisol was 0. Two
mm, the heat treatment was performed at 120 ° C. for 30 minutes, and the pulling rate was 25 mm / minute). The state of the sheared surface was visually observed.

(3) Discoloration test of coating film Using a cationic electrodeposition coated plate as an adherend, a plastisol composition was applied so that the thickness of the coating film would be 5 mm.
After heat-treating at 10 ° C for 10 minutes, topcoat paint (Super White 326 Kansai Paint Co., Ltd.) was applied to a film thickness of 5μ, and then heat-treating at 140 ° C for 20 minutes, which was used as a test piece for 200 hours with a Fedometer. The discoloration after exposure was examined.

The test results are shown in Table 3.

However, the adhesion-imparting agent was used as a 20% Dop solution.

(1) ◯: No coloring Δ: Partial coloring ×: Coloring [Effect of the invention] The plastisol composition according to the present invention exhibits excellent adhesiveness (shear strength).

Claims (1)

[Claims] 1. A plastisol comprising 100 parts by weight of a vinyl chloride polymer, 30 to 300 parts by weight of a plasticizer, 0.5 to 20 parts by weight of an adhesion promoter and 0.05 to 5 parts by weight of a thermal cleavage accelerator. In the composition, a plastisol composition containing, as an adhesion-imparting agent, a monoisopropylphenol block product of a cyanurate polymerized product of an aromatic diisocyanate.