JPH0768493B2 - Coating film forming composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coating film forming composition used as a paint or a printing ink, and is particularly applied to a highly stretchable substrate such as rubber. It relates to an effective film-forming composition.

[Conventional technology]

To color the surface of various vulcanized rubber moldings such as vehicle tires, tubes, hoses, boots or rubber exercise products, or to draw patterns such as letters and figures, it has been made of urethane resin. Paints and printing inks are used.

[Problems to be solved by the invention]

However, since the vulcanized rubber generally has poor adhesion to paints and printing inks, there is a problem that the coating film is easily peeled off even when the paints or printing inks made of urethane resin are applied.

This is because additives such as stearic acid, wax or anti-aging agent mixed in the vulcanized rubber gradually migrate to the surface of the vulcanized rubber to reduce the adhesive strength of the coating film, Due to the poor elasticity of the coating film, it is impossible to follow the expansion and contraction and bending of the vulcanized rubber.

As a countermeasure, a method of applying a urethane resin paint containing an excess of polyisocyanate (Japanese Patent Laid-Open No. 60-10298).
0), a method of activating the surface of a rubber molded article by plasma treatment and then applying a urethane resin coating compounded with excess polyisocyanate has been proposed (JP-A-60-106567). It has not been possible to solve the deterioration of the adhesive force due to the transfer of the agent and the lack of the followability of the coating film.

Also, paints and printing inks made of urethane resin are usually two-part curing type, so the pot life after mixing with a curing agent is short, and adhesion is poor due to reaction with moisture in the air during coating. However, there is also a problem in workability such as the need to further apply a top coat after application, and the pot life is short even in a one-part water-curable urethane resin. .

In this way, vulcanized rubber molding has not yet been developed, because paints and printing inks that have high followability of the coating film when applied to vulcanized rubber and that exhibit strong adhesive force over a long period of time have not been developed. When drawing patterns such as letters and figures on the surface of the vulcanized rubber molded product, the only way is to mold the pattern with separately colored rubber and then embed this in the vulcanized rubber molded product. Under the present circumstances, it is practically impossible to draw a delicate and beautiful pattern unless there is no problem even if the adhesive strength is poor.

The present invention has been made in view of the above-mentioned viewpoint, and an object thereof is to provide a coating film-forming composition having high coating film followability and exhibiting strong adhesive force to vulcanized rubber. To do.

[Means for solving problems]

A first invention of the present application is one or more rubbers selected from the group consisting of chloroprene rubber, chlorinated butyl rubber, brominated butyl rubber and nitrile rubber (hereinafter, abbreviated as "unsaturated rubber") and a block. A coating film-forming composition containing polyisocyanate as a main component.

Block polyisocyanate is diisocyanate,
It has a structure in which polyisocyanate such as triisocyanate is blocked with various organic compounds containing active hydrogen such as acetylacetone, acetoacetic acid ester, and malonic acid ester.

The block polyisocyanate dissociates and regenerates the polyisocyanate by heating, but the dissociation temperature is preferably a temperature that does not cause thermal deterioration of the coated object,
If rubber is the object to be coated, a temperature not exceeding 140 ° C,
It is preferably 130 or less and does not dissociate at room temperature, preferably 60 ° C. or less.

It is also possible to make the dissociation temperature 140 ° C. or lower by adding a basic substance such as amine to the blocked polyisocyanate having a high dissociation temperature 140 ° C. or higher.

On the other hand, any polyisocyanate can be used, but in particular, from the viewpoint of preventing yellowing of the coating film, an aliphatic or alicyclic type is preferable.

In order to produce the coating film-forming composition of the present invention, the unsaturated rubber and the blocked polyisocyanate may be mixed according to a conventional method by adding an organic solvent such as benzene, toluene, xylene, chlorobenzene or carbon tetrachloride. .

The compounding ratio is such that the blocked polyisocyanate is 0.1 to 3 parts by weight, preferably 0.2 parts by weight with respect to 1 part by weight of the unsaturated rubber.
~ 1 part by weight.

At that time, a vulcanizing agent such as zinc oxide or magnesium oxide may be added for the purpose of improving storage stability, and the rubber such as an antioxidant, an antioxidant, an ultraviolet absorber, a plasticizer or a lubricant may be added. There is no problem in adding various additives that are usually blended.

Furthermore, instead of the method of using an organic solvent, an emulsifier may be added to form an emulsion, whereby an aqueous film-forming composition can be obtained.

The coating film-forming composition thus obtained has the characteristics that the coating film has high followability and exhibits a strong adhesive force to sulfided rubber. Therefore, it is a coating material for vulcanized rubber. ,
It is the most suitable composition for use in printing ink.

That is, since this coating film-forming composition is a colorless and transparent viscous liquid, it can be used as a clear paint for imparting gloss to the surface of a rubber molded product, and a flat base (matting agent) is appropriately added. By doing so, it is possible to arbitrarily change the gloss of the rubber surface.

Further, it can be used as an enamel paint by blending a coloring pigment for paint and kneading with a roll or the like.

The coating method is the same as that for a normal one-component paint, and it may be diluted with a solvent to an appropriate viscosity for spray coating or brush coating, and then heated at about 80 to 130 ° C.

It is also possible to mix a coloring pigment or an extender pigment for a printing ink to prepare a printing ink, and it is particularly convenient to mix a pigment and a plasticizer and mix a toner color kneaded into a paste. .

As a method of use, after printing a desired pattern on the surface of the rubber by screen printing or gravure printing, a coating film of 80 to 130
It suffices to heat at about ℃, and by applying multicolor printing, it is possible to draw a delicate and beautiful pattern on the surface of the rubber.

In addition, a desired pattern may be printed on a release paper to be used as a transfer paper, or a pattern may be printed on a thin rubber cloth or a stretchable knitted fabric and then attached to the surface of rubber.

Furthermore, the coating film-forming composition of the present invention can be used as an adhesive agent when joining rubber base materials to each other, and has high followability of the coating film. Ideal for joining highly elastic rubber products such as exercise equipment.

The coating film-forming composition exhibits strong adhesive force to most industrial rubbers regardless of natural rubber (NR) or synthetic rubber, but especially chloroprene rubber (CR), nitrile rubber (NB
R) or styrene-butadiene rubber (SBR) shows extremely strong adhesion.

In addition to vulcanized rubber, it can also be used as a paint or a printing ink applied to the surface of unvulcanized rubber, paper, synthetic paper, non-woven fabric, leather, synthetic leather, synthetic resin and the like.

The coating film-forming composition can be stored at room temperature for a long period of time, and the viscosity will increase even if it is left for 10 months or more.
There is no fear that the adhesive strength will decrease.

Next, the coating film forming composition of the second invention of the present application, in the coating film forming composition of the first invention, further has a halogen in the molecule, and does not have an unsaturated bond in the main chain. It is a mixture of rubber.

The rubber having halogen in the molecule and having no unsaturated bond in the main chain is specifically a chlorinated rubber (Cl-N
R), chlorinated polyethylene (Cl-PE), chlorinated polypropylene (Cl-PP), epichlorohydrin rubber (CO, EC
O), chlorosulfonated polyethylene (CSM) and the like, and the compounding ratio thereof is 1 part by weight of rubber having a halogen or nitrile group in the molecule and having an unsaturated bond in the main chain. 0.05 to 10 parts by weight, preferably 0.1
~ 5 parts by weight.

The coating film-forming composition may be produced according to the method for producing the coating film-forming composition of the first invention, and the vulcanizing agent and other additives may be optionally added.

Further, the use and the method of use are the same as those of the coating film-forming composition of the first invention, but a rubber having a halogen in the molecule and having no unsaturated bond in the main chain is used as the coating film of the first invention. By blending with the forming composition, it is possible to obtain a coating forming composition in which the followability of the coating and the adhesive force to rubber are further improved.

[Action effect]

As described in detail above, after coating the coating film-forming composition of the first invention or the second invention of the present application on rubber, the block polyisocyanate is dissociated and coated with the rubber by heating at about 80 to 130 ° C. As a result of being integrally crosslinked with the film-forming composition, it is possible to obtain a coating film having high followability and strong adhesion.

Further, since the coating film itself has good abrasion resistance, weather resistance, light resistance, water resistance, salt water resistance, chemical resistance and ozone resistance, the coating film followability and the adhesive force to rubber are long-term. Maintained across.

Therefore, the coating film-forming composition is most suitable for use as a paint when coloring the surface of a vulcanized rubber molded product or as a printing ink for printing a predetermined pattern on the surface of a vulcanized rubber molded product. The use of this composition makes it possible to use industrial rubber moldings such as vehicle tires, tubes, hoses, boots, fenders and oil fences, or rubber suits such as wet suits, waterproof clothing and rubber shoes. An excellent effect that a delicate and beautiful pattern, which has heretofore been impossible, can be applied to the surface of a vulcanized rubber molded product having high elasticity such as a product, can be obtained.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

[Example] Preparation of coating film forming composition: Unsaturated rubber was masticated with a rubber roll. When zinc oxide and magnesium oxide were added, they were added and then uniformly mixed again with a rubber roll. After dissolving the masticated rubber in an organic solvent, it has a halogen in the molecule, and when a rubber having no unsaturated bond in the main chain is added, it is further added, and further, a blocked polyisocyanate, various Additives were sequentially added and uniformly mixed and dissolved. Table 1 shows each component and their compounding ratio (in the table, the compounding amount of each component is parts by weight, and the chemical names of the products used are shown in Table-2).

Coating film formation: By a silk screen printing method, the surface of a black wetsuit fabric made of chloroprene vulcanized rubber with a thickness of about 3 mm is shown in Table-1.
The coating film-forming composition (No. 1 to No. 8) shown in (1) is applied, dried by touch to the touch, and then at 100 ° C. for 25 minutes (only the coating film-forming composition No. 8 is about
Heated at 10 ° C). From film-forming composition Nos. 1 and 4, glossy transparent coating film, from film-forming composition Nos. 3, 7 and 8 white film, from film-forming composition No. 2 A green coating film was obtained, and a clear yellow coating film was obtained from the coating film forming composition No. 6 (thickness of each coating film was about 10 μm).

Coating film performance test: Various performance tests were performed on the black wetsuit fabric made of chloroprene vulcanized rubber on which a coating film composed of the coating film forming composition No. 1 to No. 8 was formed, and the results shown in Table 3 below. Got The comparative example in Table 3 is a commercially available urethane coating applied to the above-mentioned black wetsuit fabric made of chloroprene vulcanized rubber (film thickness: about 10 μm).

The coating film forming composition No. 2 was applied to the surface of the release paper by the gravure printing method. When this release paper was applied to a nylon jersey fabric and the above-mentioned chloroprene vulcanized rubber black wetsuit fabric and subjected to thermocompression bonding (160 ° C.) with an iron, a clear green coating film was transferred to each fabric.
When the above-mentioned various coating film performance tests were conducted on the coating film transferred to the black wetsuit fabric made of chloroprene vulcanized rubber, the same results as those shown in Table 3 were obtained for each test item.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09D 175/00 PHX (56) References JP 64-1768 (JP, A) JP 59 -6237 (JP, A) JP 59-122564 (JP, A) JP 62-20567 (JP, A) JP 63-81175 (JP, A) JP 59-48074 (JP, B2) )

Claims (6)

[Claims] 1. A coating film-forming composition comprising, as a main component, one or more rubbers selected from the group consisting of chloroprene rubber, chlorinated butyl rubber, brominated butyl rubber and nitrile rubber, and a blocked polyisocyanate. 2. The block polyisocyanate is contained in an amount of 0.1 to 3 parts by weight with respect to 1 part by weight of one or more rubbers selected from the group consisting of chloroprene rubber, chlorinated butyl rubber, brominated butyl rubber and nitrile rubber. The coating film-forming composition according to claim 1, which is blended in a proportion of 1 part. 3. The blocked polyisocyanate is 140 ° C.
The coating film-forming composition according to claim 1, which dissociates at a temperature not exceeding 10. 4. One or more rubbers selected from the group consisting of chloroprene rubber, chlorinated butyl rubber, brominated butyl rubber and nitrile rubber, a blocked polyisocyanate, and a halogen in the molecule, and A coating film-forming composition containing a rubber having no unsaturated bond in the main chain as a main component. 5. One part by weight or one or more kinds of rubber selected from the group consisting of chloroprene rubber, chlorinated butyl rubber, brominated butyl rubber and nitrile rubber is added to 1 part by weight of rubber.
The block polyisocyanate is blended in an amount of 0.1 to 3 parts by weight, and the rubber having halogen in the molecule and having no unsaturated bond in the main chain is blended in a proportion of 0.05 to 10 parts by weight, respectively. The coating film-forming composition according to item 4. 6. The blocked polyisocyanate is 140 ° C.
The coating film-forming composition according to claim 4, which dissociates at a temperature not exceeding 10.