JPH08127691A - Poly(vinyl chloride) plastisol composition - Google Patents

Abstract

PURPOSE: To obtain a poly(vinyl chloride) plastisol composition which attains both a large sag limit coating layer thickness and good coating surface and is useful as a tipping-resistant coating or a sealing material with excellent adhesion to the finish coating layer. CONSTITUTION: This plastisol composition comprises (A) 100 pts.wt. of a PVC resin, for example, a mixture of 30-90 wt.% of poly(vinyl chloride) and 10-70wt.% of a vinyl chloride-vinyl acetate copolymer, (B) a plasticizer such as dioctyl phthalate, (C) a ureaurethane fluid rheology controller and (D) an organozinc stablilizer. In a preferred embodiment, the amounts of components (A) and (B) are 100 pts.wt. and 30-300 pts.wt., respectively, components (C) and (D) are 7.5-15 pts.wt. and 2.5-7.5 pts.wt. based on 100 pts.wt. of component B, respectively where the weight ratio of C/D is 1/1-2.5/1.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a chipping-resistant paint applied to the rocker part of an automobile or the like to prevent the paint film from peeling off or being scratched, and a polychlorinated compound useful as a sealing material used in a steel plate connecting part. It relates to a vinyl plastisol composition (hereinafter referred to as a PVC sol composition).

[0002]

2. Description of the Related Art A rocker panel, a front balance panel or a lower portion of a door of an automobile is often coated with a paint having excellent chipping resistance because pebbles and the like that are flipped up during traveling easily collide with each other. This chipping-resistant paint is, for example, a PVC sol composition as disclosed in JP-A-5-43761 because of its excellent anticorrosion performance, ability to form a thick coating film, and low cost. Is commonly used.

In order to form a chipping-resistant coating film using this PVC sol composition, first, P is used as an undercoat on the surface of a steel sheet.
The VC sol composition is applied, and an intermediate coat and a top coat are formed on the surface thereof. Then, the thick PVC sol coating film formed from the PVC sol composition absorbs and absorbs the impact due to the collision of pebbles, so that the upper layer coating film is prevented from peeling off.

Further, there is a problem that it is difficult to cover the joints and joints of the steel plates with a normal paint, and moreover, water and dust easily enter the boundary and rust easily occurs.
Therefore, a sealing material made of a PVC sol composition is applied and filled in such a portion, and an intermediate coating film and a top coating film are further formed on the surface thereof. This PVC sol composition is based on a vinyl chloride resin composed of a homopolymer of vinyl chloride or a copolymer of vinyl chloride and vinyl acetate, and a plasticizer such as DOP as a base material, and also imparts adhesion such as polyamide. The agent, the filler such as calcium carbonate, and the stabilizer such as metallic soap are included. Further, in order to impart anti-sagging performance, a rheology control agent such as calcium carbonate surface-treated with fatty acid or ultrafine silica powder is generally used.

[0005]

However, the conventional PV
In the coating film structure in which the intermediate coating film and the top coating film were formed on the surface of the C sol coating film, there were cases where defective interlayer adhesion occurred between the intermediate coating film and the top coating film. As a result of diligent research, it was clarified that the cause of this adhesion failure was caused by the surface-treated calcium carbonate as a rheology control agent, and this surface-treated calcium carbonate migrated from the PVC sol coating film to the surface of the intermediate coating film. It was speculated that this would cause poor adhesion of the top coating film.

Therefore, the present inventors tried to reduce the addition amount of the surface-treated calcium carbonate, but the sag limit film thickness of the PVC sol coating film was reduced and it became difficult to make the film thicker, and the chipping resistance was improved. There was a problem of decrease. Attempts have also been made to reduce the surface treatment amount of the surface-treated calcium carbonate and to change the surface treatment agent from a fatty acid type to a rosin type or an alcohol type, but the dispersibility in the PVC sol composition decreases and the viscosity Problems such as large variations in rheological changes and reduced water resistance have appeared.

Attempts have been made to change the rheology control agent to ultrafine silica powder, etc., but there are problems that the viscosity stability and adhesiveness are lowered and the cost is high. The present invention has been made in view of the above circumstances, and has the same rheological properties as conventional ones without using surface-treated calcium carbonate, and is excellent in interlayer adhesion without deterioration in various physical properties.
The purpose is to provide a VC sol composition.

[0008]

As a result of intensive studies to solve the above problems, the present inventors have found that the desired effect can be obtained only by combining a specific rheology control agent and a specific stabilizer. It discovered and found out that the above-mentioned subject was solved. That is, the PVC sol composition of the present invention is
It is characterized in that it contains a vinyl chloride resin and a plasticizer as main components, and contains a urea-urethane liquid rheology control agent and an organozinc stabilizer.

As the vinyl chloride resin, either a vinyl chloride homopolymer or a copolymer of vinyl chloride and another vinyl monomer such as vinyl acetate can be used. It is preferable to use a mixture with the combination.
This is because the homopolymer alone may not have sufficient adhesiveness and other coating properties, and the copolymer alone may not sufficiently reduce the viscosity during bake-curing, resulting in insufficient appearance quality.

The mixing ratio of the above homopolymer and copolymer is preferably in the range of 30 to 90 parts by weight of the homopolymer and 10 to 70 parts by weight of the copolymer in 100 parts by weight of the entire vinyl chloride resin. The range of 50 parts by weight or more of the homopolymer and 20 parts by weight or more of the copolymer is particularly desirable. As a monomer other than vinyl chloride that constitutes the above-mentioned copolymer, vinyl acetate is the most common and preferable monomer, but other vinyl esters such as vinyl propionate and vinyl stearate, vinyl methyl, etc. Ethers, vinyl ethers such as vinyl isobutyl ether, maleates such as diethyl maleate, fumarates such as dibutyl fumarate, acrylic esters such as methyl acrylate, 2-hydroxyethyl acrylate and 2-ethylhexyl acrylate, Methyl methacrylate, 2-
Methacrylic acid esters such as hydroxyethyl methacrylate, acrylonitrile, vinylidene chloride and the like can be mentioned, and one or more of these can be used.
These monomers can be copolymerized with vinyl chloride in a proportion of generally 30% by weight or less, preferably 20% by weight or less.

As a plasticizer which mainly constitutes a PVC sol composition together with a vinyl chloride resin, typical examples include dioctyl phthalate (DOP), di-2-ethylhexyl phthalate, diisononyl phthalate (DINP) and the like. Examples thereof include di- and tricarboxylic acid esters such as phthalic acid ester, sebacic acid ester, and azelaic acid ester, phosphoric acid esters such as triphenyl phosphate, tricresyl phosphate, and epoxy plasticizers such as epoxidized soybean oil.

These plasticizers can be appropriately selected and used according to the physical properties such as the viscosity and curability of the intended PVC sol composition, and generally they are 30 to 100 parts by weight of vinyl chloride resin. A range of 300 parts by weight is suitable.
A part of the plasticizer can be replaced with an organic solvent as a viscosity reducing agent. In this case, as the organic solvent, it is preferable to use an organic solvent having a boiling point as high as that of the plasticizer.

A urea-urethane type liquid rheology control agent is used in the PVC sol composition of the present invention. This rheology control agent has a urea bond and a urethane bond,
For example, the trade name "BYK-LRR6237" (manufactured by BYK-Chemie GmbH) can be preferably used. This urea-urethane liquid rheology control agent is
Although the sag limit film thickness of the C sol composition increases, the plasticizer 10
The optimum range is 7.5 to 15 parts by weight with respect to 0 parts by weight. If it is less than this range, the sagging limit film thickness becomes 900 μm or less, and if it is too large, the appearance quality of the coated surface deteriorates.

The present invention is most characterized in that an organozinc stabilizer is used together with the urea-urethane liquid rheology control agent. As this organozinc stabilizer, a commercially available one which has been conventionally used for the purpose of preventing thermal decomposition of vinyl chloride resin can be used. For example, an organic composite zinc stabilizer manufactured by Akishima Kagaku Co., Ltd. can be used. Agents can be used.

The organozinc stabilizer is particularly preferably in the range of 2.5 to 7.5 parts by weight with respect to 100 parts by weight of the plasticizer. If the amount is less than 2.5 parts by weight, the sagging limit film thickness is 900μ
When it is less than m and more than 7.5 parts by weight, the appearance quality of the coated surface deteriorates. The amount of the organozinc stabilizer added is preferably determined according to the amount of the urea-urethane liquid rheology control agent added, and the weight ratio of the rheology control agent / stabilizer = 1/1 to 2. The range of 5/1 is particularly preferred.

In addition to the above, a filler, an adhesiveness-imparting agent, another stabilizer, a pigment, and other additives may be appropriately used in the PVC sol composition of the present invention depending on the purpose. As the filler, calcium carbonate, magnesium carbonate, carbonates and sulfates of alkaline earth metals such as barium sulfate,
Mica, silica, talc, diatomaceous earth, kaolin, calcium oxide and the like are exemplified, and these can be used alone or in combination of two or more kinds. In addition, organic powders such as cellulose powder and powdered rubber can be used if necessary.

The amount of the filler compounded is preferably in the range of 30 to 200 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. If it is less than 30 parts by weight, the cohesive force becomes insufficient,
If it exceeds 200 parts by weight, it becomes brittle and the flexibility and adhesiveness deteriorate. The adhesion-imparting agent enhances the adhesion of the PVC sol coating film to the article to be coated, and conventionally-used adhesion-imparting agents such as epoxy-based, acrylic-based, polyamide-based, isocyanate-based can be used. . Among them, polyamide, block urethane prepolymer, block isocyanurate and the like are particularly preferable.

Other stabilizers include lead, barium, tin,
Metal salts such as calcium can be used as before.
The blending amount is appropriately determined according to the blending amount of the organozinc stabilizer. The PVC sol composition of the present invention can be applied with an arbitrary thickness by a conventional coating means such as airless spray, and is heated to a conventional baking temperature of 120 to 160 ° C. to form a coating film. can do.

[0019]

When a liquid rheology control agent of urea-urethane type is used, the interlayer adhesion failure between the intermediate coating film and the top coating film as in the conventional surface-treated calcium carbonate does not occur, but this alone is sufficient for the sagging limit film. I can't get the thickness. Further, the organozinc stabilizer alone has an effect as a stabilizer, but has no effect of increasing the sag limit film thickness. further,
Even if the urea-urethane liquid rheology control agent and other stabilizer are used in combination, the effect of increasing the sag limit film thickness cannot be obtained.

In the PVC sol composition of the present invention, however, the combined use of the urea-urethane type liquid rheology control agent and the organozinc stabilizer improves the interlayer adhesion between the intermediate coating film and the top coating film. And the sagging limit film thickness is significantly increased. Although the reason for this is not clear, some reaction such as a complexation reaction occurs between the organozinc stabilizer and the urea-urethane liquid rheology control agent, and the urea-urethane liquid rheology control is performed. It is speculated that the action of the agent will increase.

[0021]

EXAMPLES The present invention will be specifically described below with reference to examples. A PVC sol having the following composition was used as a basic sol. Resin for vinyl chloride paste 50 parts by weight (PVC paste "G-121" manufactured by Nippon Zeon Co., Ltd.) Resin for vinyl chloride blend 50 parts by weight (PVC blend "G-51" manufactured by Nippon Zeon Co., Ltd.) Plasticizer (adipine Acid-based polyester) 100 parts by weight ("PN-160" manufactured by Asahi Denka Kogyo Co., Ltd.) Adhesiveness imparting agent (polyamide resin) 6 parts by weight ("Nuri Bond 262" manufactured by Akzo Co., Ltd., amine value 195) Agent (aliphatic hydrocarbon solvent) 20 parts by weight (“EXXSOL D-80” manufactured by Exxon Corporation) ───────────────────────── Total 226 parts by weight of basic sol (Example 1) As shown in Table 1, the above basic sol 226
5 parts by weight of urea-urethane liquid rheology control agent ("BYK-LRR6237" (BYK-Chemie GmbH))
Part by weight and 5 parts by weight of an organic composite zinc stabilizer (“LT-89A” manufactured by Akishima Chemical Co., Ltd.) were mixed and mixed for 30 minutes using a kneader with a pressure reducing device, followed by defoaming for 60 minutes. 1
A PVC sol composition of was obtained. (Examples 2 to 7) Urea-urethane type liquid rheology control agent ("BYK-LRR6237" (manufactured by BYK-Chemie GmbH)) and organic composite zinc stabilizer ("LT-89A" manufactured by Akishima Chemical Co., Ltd.) ) PVs of Examples 2 to 7 in the same manner as in Example 1 except that the addition amount of) was changed variously as shown in Table 1.
A C sol composition was obtained. (Comparative Examples 1 to 5) Urea-urethane type liquid rheology control agent (“BYK-LRR6237
The PVC sol compositions of Comparative Examples 1 to 5 were obtained in the same manner as in Example 1 except that the addition amount of "(BYK-Chemie GmbH)" was changed as shown in Table 1. (Comparative Examples 6 to 8) The organic composite zinc-based stabilizer ("LT-89
A ”PVC sol compositions of Comparative Examples 6 to 8 were obtained in the same manner as in Example 1 except that the addition amount of“ A ”manufactured by Akishima Chemical Co., Ltd. was changed variously as shown in Table 2. (Comparative Examples 9 to 10) With respect to 226 parts by weight of the basic sol, a urea-urethane liquid rheology control agent (“BYK-LRR623
7 "(manufactured by BYK-Chemie GmbH), lead-based stabilizers (" Neobase "manufactured by Sakai Chemical Co., Ltd.), organotin-based stabilizers (" OT-9 "instead of organozinc-based stabilizers). The PVC sol compositions of Comparative Examples 9 to 10 were obtained in the same manner as in Example 1 except that 5 parts by weight of Asahi Denka Kogyo Co., Ltd. was added. (Comparative Examples 11 to 12) Based on 226 parts by weight of the basic sol,
Instead of the urea-urethane type liquid rheology control agent, fatty acid surface-treated calcium carbonate (“CC-R” manufactured by Shiraishi Calcium Co., Ltd.) was added at the addition amount shown in Table 2 and no stabilizer was used. In the same manner as in Example 1, PVC sol compositions of Comparative Examples 11 to 12 were obtained. (Comparative Examples 13 to 15) Based on 226 parts by weight of the basic sol,
75 parts by weight of fatty acid surface-treated calcium carbonate (“CC-R” manufactured by Shiraishi Calcium Co., Ltd.) was used in place of the urea-urethane liquid rheology control agent, and an organic composite zinc-based stabilizer (“LT-89A” Akishima Kagaku) was used. PVC sol compositions of Comparative Examples 13 to 15 were obtained in the same manner as in Example 1 except that the amount added in Table 2 was used. (Comparative Examples 16 to 18) Based on 226 parts by weight of the basic sol,
Ultrafine particle silica (“Aerosil # 380” manufactured by Nippon Aerosil Co., Ltd.) was added in the amount shown in Table 2 instead of the urea-urethane liquid rheology control agent, and no stabilizer was used. Comparative Example 16
~ 18 PVC sol compositions were obtained. (Comparative Examples 19 to 21) Based on 226 parts by weight of the basic sol,
10 parts by weight of ultrafine particle silica (“Aerosil # 380” manufactured by Nippon Aerosil Co., Ltd.) was used in place of the urea-urethane liquid rheology control agent, and an organic composite zinc stabilizer (“LT-89A” Akishima Chemical Co., Ltd.) was used. Comparative Examples 16 to 18 were obtained in the same manner as in Example 1 except that (a) was added in the amount shown in Table 2. (Test) With respect to the PVC sol composition of each of the above Examples and Comparative Examples, the sag limit film thickness, the adhesion of the top coating film and the state of the coated surface were tested, and the results are shown in Tables 1 and 2. The test conditions are as follows. <Dripping limit film thickness> Prepare an electrodeposition coated plate of 100 × 300 mm, apply each PVC sol composition in a wedge-shaped cross section with an applicator so that the film thickness gradually changes to 0 to 2000 μm, and immediately It was placed vertically and kept at 25 ° C. for 30 minutes. At this time, the coating film is in a state in which the film thickness is inclined in the horizontal direction. After that, baking was performed at 120 ° C. for 30 minutes, and the film thickness at the maximum film thickness portion where the sagging occurred was measured to be the sagging limit film thickness. <Adhesion of Topcoat Film> Each PVC sol composition is applied to a 70 × 150 mm electrodeposition coated plate by airless spraying to a film thickness of 600 μm, and preheated at 110 ° C. for 10 minutes. Next, after cooling to room temperature, 1 piece of alkyd-melamine intermediate coating composition (“TP-37” manufactured by Kansai Paint Co., Ltd.)
A 5 μm-thick PVC sol coating film was applied with an air spray, set for 10 minutes, and then baked at 140 ° C. for 30 minutes. After cooling to room temperature, acrylic-melamine topcoat paint (“NEO # 6000” manufactured by Kansai Paint Co., Ltd.)
Was coated on the surface of the intermediate coating film by air spraying to a film thickness of 25 ± 5 μm, set for 10 minutes, and then baked at 140 ° C. for 30 minutes.

Each coated plate has a temperature of 20 ° C. and a humidity of 60%
Left in standard environment for 24 hours, then JISK5
A grid pattern (2 × 2 mm) defined by 400 was carved, and a cellophane tape peeling test was performed to evaluate the adhesion of the top coat film. The results show the number of squares cut in the denominator and the number of remaining topcoat coatings attached to the numerator. <Coating state> Using an airless pump with an air ratio of 40: and an airless nozzle tip "163-519" (manufactured by Nippon Gray Co., Ltd.), a gun source pressure of 10MP
a, gun distance 300 mm, gun speed 300 mm / se
Each of the PVC sol compositions was applied under the conditions of c and a temperature of 35 ° C., and the state of the coated surface (presence or absence of unevenness and tail) was visually evaluated. In the results, when the conventional product of Comparative Example 11 was evaluated as ◯, ◎ was superior to that, Δ was slightly inferior to that, and x was significantly inferior.

[0023]

[Table 1]

[0024]

[Table 2]

(Evaluation) From the results of Comparative Examples 1 to 5, urea-
It can be seen that when the urethane rheology control agent is used alone, the adhesion of the top coat film is good, but the effect of increasing the sag limit film thickness is small and it is necessary to add a large amount. It is also clear from the results of Comparative Examples 6 to 9 that the organozinc stabilizer alone does not have the effect of improving the sag limit film thickness. However, in the examples, even with a small amount of the urea-urethane type rheology control agent, the sag limit film thickness is remarkably improved, and the coating surface is also good. This is because the urea-urethane type rheology control agent and the organozinc stabilizer are used. It is clear that the combined use of and is a synergistic effect.

Further, from the results of Comparative Examples 9 to 10, even if the urea-urethane type rheology control agent and other stabilizers were combined, the synergistic effect as in the Examples was not observed. Furthermore, by comparing the respective comparative examples, it was found that the surface-treated calcium carbonate inhibits the adhesion of the top coating film, and even if a combination of a rheology control agent other than urea-urethane and an organozinc stabilizer was used, It can be seen that the sagging limit film thickness is not improved, and rather the adverse effect that the coated surface state is deteriorated is occurring.

[0027]

According to the polyvinyl chloride plastisol composition of the present invention, the same flow characteristics as the conventional one can be maintained, a large sag limit film thickness and a good coating state can be achieved, and the adhesion of the top coating film can be achieved. It is possible to reliably prevent the occurrence of defects.

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Claims (1)

[Claims] 1. A polyvinyl chloride plastisol composition comprising a vinyl chloride resin and a plasticizer as main components, and a urea-urethane liquid rheology control agent and an organic zinc stabilizer.