JPS59113078A - Stain-proofing agent - Google Patents

Abstract

PURPOSE:To provide a stainproofing agent curable rapidly at room temperature merely by coating without necessitating heating operation and other troublesome procedures, and capable of giving a stainproofing coating film having high adhesivity and durability, by using specific plural kinds of linear diorganopolysiloxanes, a specific crosslinking agent and a catalyst as the components. CONSTITUTION:The objective stainproofing agent can be prepared by compounding (A) 100pts.wt. of a diorganopolysiloxane component containing (i) a linear diorganopolysiloxane having one or more functional groups at each of both terminals and (ii) a linear diorganopolysiloxane having no functional group or one or more functional groups at either of the terminal groups at a weight ratio (i/ii) of 90/10-20/80 with (B) preferably 10-100pts.wt. of a crosslinking agent having plural functional groups capable of effecting the addition condensation reaction with the functional group of the component (A) (preferably polyacetoxysilane) and (C) preferably 0.1-30pts.wt. of a catalyst such as dibutyl acetate, etc. USE:Prevention of the running of and the staining with printing ink.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-staining agent, and particularly to an anti-staining agent that is excellent in preventing bleeding and staining of printing ink.

There often arises a need to temporarily or semi-permanently protect the surfaces of articles from contamination. For example, in the process of applying paint or other coating liquid, there are cases such as preventing contamination from adhering to the back side, partially covering areas where you do not want paint to adhere, and preventing contamination at the end of the packing roll. be.

Particularly important is the field of printing, which can be called an imagewise coating process. In other words, in various printing methods such as letterpress, lithography, screen printing, collotype, etc., ink may adhere to the non-image areas of the printing plate during printing, resulting in stains and image bleeding on the printed matter, which is a major problem. It is a point. For example, in letterpress printing and flexible printing, there is a phenomenon called "bottoming" in which ink adheres to non-image areas. In the case of printing that still uses a metal mask, Japanese Patent Application Laid-Open No. 56-679
85 Printing ink is applied to the back side of the mask (the side that comes into contact with the printing material) as described in ``Ink printing method using metal δ printing''.

There is a problem in that smearing occurs at the printing boundary on the printing substrate, making the printing unclear. In order to solve these problems, the non-image areas of the printing plate and the back surface of the metal mask can be treated to make them ink repellent and stain resistant, and such a treatment agent is desperately needed.

Conventionally, for the purpose of preventing such contamination, methods have been known in which a fluororesin such as polytetrafluoroethylene or a water/oil repellent resin coating such as silicone resin is formed on the surface of the article to be prevented from contamination (for example, Kaisho 56-6
No. 7985, Japanese Unexamined Patent Publication No. 130748/1983).

However, the formation of these resin films generally requires high-temperature treatment, which limits the substrates to which they can be applied, and the shredding operation is complicated. Furthermore, these resins have poor adhesive properties,
This is because adhesion tends to worsen as the coating treatment conditions become milder.

The reality is that it is almost impossible to obtain a film with practical adhesive properties under mild conditions ranging from room temperature to several tens of degrees Fahrenheit.

In view of these circumstances, the present inventors have developed a highly durable material that does not require any particular heating or troublesome operations, can be applied to substrates with poor heat resistance, quickly cures at room temperature just by applying it, and has good adhesion and durability. Results of intensive study on antifouling agents that form a fouling film 1
We have arrived at the present invention.

That is, the present invention relates to an antifouling agent containing the following components (a) to (d).

(a) Linear diorganopolysiloxane having one or more functional groups at both ends (b) Linear diorganopolysiloxane having no functional group or having one or more functional group only at one end (c) A crosslinking agent having a plurality of functional groups capable of condensation or addition reaction with the functional group (d) Catalyst for the crosslinking reaction Linear diorganopolysiloxane used as components (a) and (b) in the present invention is a substance represented by the following general formula (I). , R, R', R", R": an alkyl group having 1 to 10 carbon atoms.

Alkenyl group, aryl group Even if it has a substituent good.

X, X': H0ge7, H,OH,0COR
,.

OR2゜ (R1-R6 are alkyl or (substituted alkyl group) functional group.

n: An integer from 100 to 10,000.

T'+q: O≦p, q≦6 integer.

And what is the linear diorganopolysiloxane having one or more functional groups at each end as referred to in component (a)?

In the above general formula, 1≦p≦6, 1≦q≦6, and linear organopolysiloxane that does not have the functional group of component (b) or has one or more functional groups only at one end. In general formula (1), p-q-O9 or 1≦p≦3. This is the case when q=o or p−〇, 1≦q≦6.

In these, RH/// may be the same or different, and the repeating units may be different along the polymer chain. Generally, 60% or more of R and R' are methyl groups, and 40 or less are vinyl groups.

A phenyl group is desirable. x and x' may be the same or different. The diorganopolysiloxas of components (a) and (b) may be used alone or in combination of two or more different types.

The crosslinking agent of component (c) is a functional group X in general formula (1).
.

It is a silicon compound that has a plurality of functional groups, preferably six or more, that can cause a condensation or addition reaction with X/ (or a functional group newly generated when these undergo a change such as hydrolysis). Among these, especially the following general formula (II)
Preferably, those having the structure represented by the above or condensates thereof.

Xllll5IR4-In(■) (where m is an integer of 2≦m≦4) Here, X and R have the same meaning as explained in the general formula (1). These crosslinking agents may be used alone or in combination of two or more different types.

The catalyst (d) is a substance that promotes the condensation or addition reaction between the functional groups contained in the substances (a) and (b) and the functional group contained in the substance (c). .

Specifically, organic carboxylates of metals such as tin, zinc, and lead 2, such as dibutyltin acetate, dibutyltin laurate, octenoic acid, zinc octenoate, lead naphthenate, and substances such as chloroplatinic acid are used. It will be done.

The preferred composition ratio of the antifouling agent used in the present invention is as follows.

1) Diorganopolysiloxane component 100 parts by weight 2) Crosslinking agent 6 to 200 parts by weight 3) Catalyst
Medium: 01 to 50 parts by weight What is the diorganopolysiloxane component?

It is a mixture of one or more selected from component (a) and one or more selected from component (b). The ratio of component (a) to component (b) is preferably in the range of 9515 to 10/90 by weight, and preferably in the range of 90/10 to 20/80.

Furthermore, in order to improve the strength of the silicone rubber thin film, various fillers can be mixed with the silicone rubber. Further, in order to color the coating film and make it easier to see, coloring agents such as dyes and pigments, and further various other additives may be mixed.

As a solvent when forming the above-mentioned antifouling agent.

Paraffinic hydrocarbons, paraffinic hydrocarbons, cycloparaffinic hydrocarbons, aromatic hydrocarbons, carboxylic acid alkyl esters, ethers.

Although ketones, halogenated hydrocarbons, and mixtures thereof are advantageously used, it is particularly preferable to use paraffinic or isoparaffinic hydrocarbons as the main component from the viewpoint of coatability. Typical examples of such hydrocarbons include fractionated petroleum products and reformed products thereof.

Among these antifouling agents, diorganopolysiloxanes/linear diorganopolysiloxanes having substantially hydroxyl groups at both ends as the component (a), and hydroxyl groups substantially at only one end as the component (b) Linear diorganopolysiloxanes, or linear diorganopolysiloxanes that have substantially no functional groups (both have a number average molecular weight of 5,000 to
1,00. ．． 0.000).

As the crosslinking agent for component (C), it is preferable to use a polyacetoxysilane represented by the following formula (III) or a condensate thereof, which exhibits good curability, adhesive properties, and storage stability of the solution.

R4-m5i(OCOCH3)lIl(■) (m: 6 but not 4) Here, R is the same as described above. When such a composition is used, it is particularly preferable to use a tin compound such as dibutyltin acetate, dibutyltin laurate, or silver octenoate as the catalyst for component (d), which has substantially no functional group in component (b). Examples of linear diorganopolysiloxanes include 9, 5H-200 (Toray Silicone), K
Commercially available products such as F-96H (Shin-Etsu Chemical (Ha),) etc.
Products with various viscosities are commercially available, but especially those with viscosities from 1,000 to 100. It is preferable to use relatively high viscosity DO locentistokes.

A preferable mixing ratio of these is 100 parts by weight of diorganopoly'/loxane component (weight ratio of component (a) and component (b) 9515 to 10/90, preferably 90/10 to 2).
5 to 200 parts by weight, more preferably 10 to 100 parts by weight, of the polyacetoxysilane (or condensate thereof) represented by formula III).

Catalyst 0.05 to 50 parts by weight, more preferably 01 to 30 parts by weight
Parts by weight. If the amount of polyacetoxysilane added is too small, sufficient adhesive strength will not be obtained and the storage stability of the solution will be reduced, while if it is too large, curing will be delayed and stain resistance will be reduced.

If the amount of catalyst is too small, the curing will be delayed, and if it is too large, the stain resistance will be reduced, and the coating film may deteriorate over time when stored for a long time.

The concentration of the solution depends on the molecular weight of the diorganopolysiloxane used, the type of solvent, and the coating method, but is generally 5 to 50% by weight, or preferably 10 to 60% by weight. Do not apply if it is too thin or too thick.

A precone rubber coating film with an appropriate thickness cannot be obtained.

The antifouling agent of the present invention has the following structure.

For example, brushes, brushes, cloth, cotton swabs, sponges, pipettes.

It can be applied to the required area using various application tools such as droppers and syringes. After application, it can be heated using suitable vortexing means to promote curing and adhesion.

In order to improve adhesion, a suitable material may be applied as a primer prior to application of the antifouling agent of the present invention.

The coating composition of the present invention can be applied to any material. In particular, a base material with poor heat resistance because it does not require heating for coating.

For example, it can be applied to paper, cloth, soft resin, etc., and its uses are extremely diverse.

There are various possible uses for the antifouling agent of the present invention, but 2
% is useful in the printing field as already mentioned. By applying the antifouling agent of the present invention to the non-image areas of printing plates or the back side of metal masks in various types of printing, it is possible to prevent ink stains and image bleeding and obtain clear printed matter. In the case of offset printing, the same effect can be obtained even if the coating is applied to the portion of the blanket corresponding to the non-printing area during the coating step 9 on the printing plate.

In addition, when printing with a high level of ink, before the ink film transferred onto the printing plate surface or substrate is dried or cured, smooth it with a roll made of a material that does not stain with ink. Smoothing pinholes or smoothing the film surface to make it glossy is an effective means for obtaining good printed matter, but it is effective to coat the surface of such a roll with the antifouling agent of the present invention. be.

As described above, the present invention greatly contributes to imparting stain resistance to various articles.

Claims (1)

[Claims] (1) A stain preventive agent containing the following components (a) to (d). (a) Linear diorganopolysiloxane having one or more functional groups at both ends (b) Linear diorganopolysiloxane having no functional group or having one or more functional group only at one end (C) a crosslinking agent having a plurality of functional groups capable of causing a condensation or addition reaction with the functional group; (d) a catalyst for the crosslinking reaction;