JPH04224877A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain a coating composition from a crosslinking vinyl chloride resin as a principal film constituent. CONSTITUTION:A vinyl chloride resin is mixed with a quaternary ammonium salt, a polyepoxy compound, a curing agent for epoxy resin, a ckosslinking agent, a stabilizing agent, an antifoaming agent, a solvent, a pigment, a plasticizer, etc., to give a coating composition which is most suitable for an undercoating, intercoating, and top coating or a single-layer coating for objects such as a plate or mass of metal, such as iron, aluminum, gallium, barium, stainless steel, titanium or copper, and a formed article such as an automobile, sheathing material, a water tank, etc.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition that is excellent in weather resistance, color fastness, adhesion, elasticity, processability, and heat resistance, and is inexpensive.

0002

[Prior Art] In general, coating compositions include polyurethane resins, polyacrylic resins, epoxy resins, polyester resins, and fluorocarbon resins as the main components of the coating film, to which pigments and solvents are added, and which are air-drying, Or it was a baked type.

0003

However, this type of coating composition has disadvantages such as deterioration by ultraviolet rays, lack of weather resistance, undesirable phenomena such as fading of color and efflorescence of the plasticizer, and lack of durability. In addition, fluorine paint requires two to three coats, is expensive, requires many steps, and has the disadvantage that cracks occur during bending. Furthermore, conventional paints lacked adhesion and had a heat resistance temperature of 50°C.
In addition, it lacks elasticity and processability, and the resin itself is not cheap. Furthermore, there has been no coating composition in which a vinyl chloride resin is used as the main component of the coating and the coating film has a network structure (crosslinked type).

0004

[Means for Solving the Problems] The present invention uses a vinyl chloride resin as the main component of the coating film, and optionally a vehicle consisting of a quaternary ammonium salt, a polyepoxy compound, a crosslinking agent, a stabilizer, and a solvent. Add pigment, mix and dry,
The present invention provides a coating composition that is crosslinked by baking to provide chemical resistance, heat resistance, adhesiveness, and weather resistance, and is inexpensive.

[0005]

[Example] An example of the coating composition according to the present invention will be described below. That is, in the present invention, polyvinyl chloride resin is used as the main component of the coating film, and a crosslinking agent, adhesive,
It is a liquid paint with a composition containing a solvent, antifoaming agent, and stabilizer. To explain further, vinyl chloride resins include polymers of vinyl chloride alone, vinyl chloride and vinyl acetate, acrylic esters, vinyl ethers, vinyl esters,
It is made of one type of copolymer with ethylene or the like. Note that the viscosity of the vinyl chloride resin can be reduced by changing the molecular weight. In the present invention, the quaternary ammonium salt that acts as a catalyst is a compound represented by the chemical formula R4NX, where R represents an alkyl group such as a methyl group or an allyl group such as a benzyl group, and the four Rs are the same. Even if they are present or different types, any of them can be used as the quaternary ammonium salt of the present invention. Heterocyclic ammonium salts in which R's are bonded to each other to form a ring, such as N-methylpyridinium salts, can also be used equally. In the formula, N represents a nitrogen element. X in the formula is a halogen element represented by chlorine, an acid group such as a sulfone group, or a nitric acid group, and is not related to the type of acid group. The amount of the quaternary ammonium salt added is in the range of 0.02 to 10 parts by weight per 100 parts by weight of the vinyl chloride resin.

In the present invention, the polyvalent epoxy compound that functions as a crosslinking agent and adhesive is a compound having two or more epoxy groups in one molecule. For example, epoxidized soybean oil, epoxidized linseed oil, commonly known as epoxy resin obtained by condensing epichlorohydrin and bisphenol A, etc. Compounds that have a certain degree of compatibility with vinyl chloride resins or their plasticizers. It is. The amount of the polyvalent epoxy compound is in the range of 1 to 50 parts by weight based on 100 parts by weight of the vinyl chloride resin.

The epoxy resin curing agent used in the present invention is a conventional epoxy resin curing agent. Specific examples thereof include one of amine compounds, diamine compounds, polyamine compounds, polyamides, amino acids, polybasic acids having two or more carboxyl groups, and acid anhydrides thereof. Since the reaction between the amine curing agent and the epoxy compound is extremely fast, it is often unsuitable for the usage conditions of general vinyl chloride resins, but it is useful for paints. In addition, curing agents suitable for the general reaction conditions are amino acids such as ε-aminocaproic acid, dibasic acids such as adipic acid, acid anhydrides such as succinic anhydride, maleic anhydride, phthalic anhydride, trimellitic anhydride, etc. Acids such as pyromellitic anhydride, methylhexahydrophthalic anhydride, and condensates of these polybasic acids and glycol are useful and can be used alone or in combination. The amount of the epoxy resin curing agent is in the range of 0.2 to 20 parts by weight based on 100 parts by weight of the vinyl chloride resin.

[0008] As the plasticizer used in the present invention, for example, dioctyl phthalate can be used as desired. Therefore, the present invention provides a coating composition containing a wide range of crosslinked vinyl chloride resins ranging from hard to soft.

Solvents used in the present invention include methyl ethyl ketone (MEK), thinner, and cyclohexane (CH
N), toluene, etc., and the viscosity of the vehicle whose main component is vinyl chloride resin is about 10 to 500 CP.
It is diluted to S position.

Since the stabilizer used in the present invention directly acts on the crosslinking reaction of the vinyl chloride resin, its type and amount are arbitrary. Examples include dibasic lead phthalate, zinc laurate, etc., and the amount added is 10% of vinyl chloride resin.
It is 0.5 to 5 parts by weight relative to 0 parts by weight.

[0011] The pigments used in the present invention are composed of one or more types of pigments, such as coloring, rust prevention, and physical properties.For example, there are two types: organic and inorganic.The organic pigments include azo pigments, polycyclic pigments, etc. , one or more of these are used. Inorganic pigments include titanium dioxide, carbon black, iron oxide,
These include pearl, yellow lead, molybdate orange, zinc white, aluminum, copper, kaolinite, talc, hallosite, calcium carbonate, barium sulfate, silica, and aluminum oxide. Further, the antifoaming agent is silicon or the like.

[0012] Here, the crosslinking reaction mechanism of the main elements of the coating film used in the present invention and the structure of the crosslinked product will be explained. That is, the quaternary ammonium salt acts as a catalyst and introduces oxygen from the air into the polyvinyl chloride molecule, producing hydroxyl groups and carboxyl groups at various locations in the polyvinyl chloride molecular chain. The hydroxyl group generated in this chain reacts with the carboxyl group of one of the polyhydric carboxylic acids or its acid anhydrides blended as a curing agent to form an ester bond, and the remaining carboxyl groups are therefore generated in the chain. It is to be done.

[0013] In this way, the carboxyl group generated in the polyvinyl chloride chain reacts with the epoxy group to form an ester bond, and when amines or amino acids are used as a curing agent, they react with the amino group. to generate an amide bond.

As mentioned above, at the same time as the carboxylation of polyvinyl chloride molecules, the reaction between the polyvalent epoxy compound and the curing agent also proceeds in parallel, and the formation of so-called epoxy resin also proceeds, but naturally the reaction to form an epoxy resin proceeds. Part of the process also involves reactions with carboxyl groups in polyvinyl chloride chains.

Therefore, the crosslinked vinyl chloride resin used in the present invention has an infinite network structure mainly crosslinked with epoxy resin, and while the heat resistance temperature of non-crosslinked vinyl chloride resin moldings is about 60°C. , which is the main element of the coating film that does not change even at temperatures above 300°C.

Example 1 Polyvinyl chloride
100 parts dibasic phthalic acid (stabilizer)
3-part epoxidized linseed oil (
crosslinking agent, adhesive)
5 parts adipic acid (curing agent)
1.5 parts Tetrabutylammonium bromide (catalyst)
0.5x MEK (solvent)

Mix 150 parts of the above substances, set the paint viscosity to 50 CPS, and coat it on a galvanized iron plate with a curtain flow coater to approx.
It was applied at a thickness of 0 microns (wet), preheated at 100°C for about 15 minutes, baked at 200°C for 1 to 3 minutes, and then slowly cooled to form a coating film of about 20 microns (dry).

Example 2 Polyvinyl chloride
100 parts dibasic phthalic acid (stabilizer)
3-part epoxidized linseed oil (
crosslinking agent, adhesive)
5 parts adipic acid (curing agent)
1.5 parts Tetrabutylammonium bromide (catalyst)
0.5x cyclohexane (solvent)
140
titanium dioxide (pigment)
25 parts The above substances were mixed uniformly, the viscosity was set to 100 CPS, and this was applied to an aluminum plate at a thickness of about 100 microns (wet) using a roll coater, and after preheating at 100°C for about 8 minutes, 23
It was baked at 0°C for 1 minute and then slowly cooled to form a white coating film with a thickness of 40 microns.

Example 3 Polyvinyl chloride
100 parts dioctyl phthalate (plasticizer)
30 parts zinc laurate (stabilizer)

2-part epoxidized soybean oil

3 parts trimellitic anhydride (curing agent)
1.5 parts trimethylbenzylammonium chloride
0.5 part trimethylanilium chloride
0.5 part methyl ethyl chloride (solvent)
100 parts of the above materials were uniformly mixed, the viscosity was 80 CPS, and the mixture was sprayed onto a galvanized iron plate at 30°C using a spray gun, preheated at 100°C for about 15 minutes to vaporize the solvent, and then baked at 200°C for 2 minutes. , and then slowly cooled to form a coating film.

Example 4 Component A Vinyl chloride-vinyl acetate copolymer
100 parts barium laurate (stabilizer)
Trimethylammonium chloride (catalyst)
0.5 part epoxy resin (adhesive, crosslinking agent) 5
Silicone (antifoaming agent)
1 part adipic acid (curing agent)
2 parts MEK (solvent)

150 parts B component epoxy resin (crosslinking agent, adhesive)
2 parts maleic anhydride (curing agent)
2-part ketone ester (solvent)
6 parts The above ingredients were mixed at 30°C, and the viscosity was 50CPS (30°C).
This is coated on a steel plate with a roll coater for 50 minutes.
It was coated with a micron (wet) coating, dried, baked, and slowly cooled to form a coating film with a thickness of 25 microns.

Comparative example polyvinyl chloride
100 parts zinc laurate (stabilizer)
1 part MEK (solvent)

150 parts silicone (antifoaming agent)

One part of the above substances was mixed and coated on an iron plate to a thickness of 100 microns using a curtain flow coater. Thereafter, a coating film was formed in the same manner as in Example 4.

Table 1 However, ◎ is excellent, ◯ is good, △ is average, and × is poor. In addition, stain resistance was measured in Examples 1 to 4 by specular gloss measurement at 60°C.
was ranked 10th, and Comparative Example was ranked 3rd. Workability is directly related to bending resistance. In addition, ■ is the degree of ultraviolet deterioration, and ■ is JIS-K.
-7217, 300℃ for Examples 1 to 4, 60℃ for comparative example
Deformed peeling, ■ is a goban test (peeling in 100/100 sellotape test), ■ JIS-D-0205, ■ is 1
This is the presence or absence of cracks and peeling that occur in the coating film when it is bent 100 times at 90° T (thickness of the adhered plate).

[0022]

Effects of the Invention As described above, according to the coating composition of the present invention, unlike the conventional linear polymer, the coating film has a network (crosslinked) structure and thus has (a) adhesive properties. , (b) weather resistance, (c) heat resistance, (d) crack resistance, (e) chalking resistance, (f) stain resistance, (g) hardness, and (h) workability. It has the characteristic that it can be used for plates, blocks, and molded bodies of aluminum, copper, stainless steel, galvalume, plastic, wood, etc. Furthermore, since there is no deterioration in gloss, it has excellent stain resistance. Furthermore, it has features such as easier coating and curing workability than before, and faster drying and baking. In addition, the coating composition according to the present invention has excellent rust prevention, water resistance, and chemical resistance, and has the advantage that it can be used on plastics, wood, automobiles, ships, construction materials, and other harsh conditions. In addition, the present coating composition has the characteristic that it has initial performance as a standalone composition without being laminated like other conventional coatings.

Claims (3)

[Claims] 1. A coating composition comprising a vinyl chloride resin, a quaternary ammonium salt, a polyvalent epoxy compound, an epoxy resin curing agent, a crosslinking agent, and a solvent. 2. The coating composition according to claim 1, further comprising a pigment. 3. The coating composition according to claim 1, further comprising at least one of a plasticizer, an adhesive, and a stabilizer.