JPH0269559A - Reduction of tackiness of urethane elastomer - Google Patents

Abstract

PURPOSE:To reduce the post-application surface tackiness of an ordinary temperature-curable urethane elastomer applied to sealers, etc., by compounding a specific amount of a drying oil when a urethane prepolymer is mixed, reacted and cured with a curing agent. CONSTITUTION:(C) 0.1-5wt.% of a drying oil (e.g., linseed oil or tung oil) is compounded with a mixture of (A) a urethane prepolymer having terminal isocyanate groups and a curing agent comprising (B) a compound having active hydrogen atoms (e.g., ethylene glycol) and, as necessary, a plasticizer, catalyst, defoaming agent, filler, etc.

Description

[Detailed description of the invention] [Industrial application field]

The present invention aims to improve room temperature curing urethane elastomers used for civil engineering and construction, and more specifically, to improve sealing materials,
This invention relates to a method for eliminating surface viscosity after construction in room-temperature curing urethane elastomers used as waterproofing materials. (Background) Room-temperature curable urethane elastomers, which are currently widely used as sealants, waterproofing materials, etc. in the civil engineering and construction fields, include, for example, urethane prepolymers with terminal isocyanate groups, polyether polyols, 3,3°-dichloro-4, Injecting or applying a composition prepared by mixing a compound having active hydrogen such as 4-diaminodiphenylmethane with a hardening agent containing a plasticizer, a catalyst, an antifoaming agent, a filler, etc. in a predetermined ratio to the work site. formed by. The obtained urethane prepolymer has excellent rubber elasticity, weather resistance, chemical resistance, water resistance, etc., and is therefore widely used as a sealing material and waterproofing material for the roofs and walls of buildings. (Problems with conventional technology) However, with such conventional urethane prepolymers, stickiness remains on the surface of the polymer layer for a long time after application.
For this reason, there has been a problem in that the surface is easily contaminated by dust and the like after construction. So as a countermeasure. (1) A method of increasing the amount of a metal catalyst such as octyl lead-resistant or dibutyltin dilaurate, or using an acid catalyst such as octylic acid or phthalic acid in combination. (2) A method in which the number of functional groups in the polyether polyol in the urethane prepolymer or curing agent is made larger than usual. etc. are being carried out. However, in these conventional methods for reducing surface tackiness, (1) shortens the pot life after preparation, making it difficult to apply and resulting in a poor finish, and (2),
The physical properties of the resulting elastomer layer, especially its elongation, deteriorate, resulting in drawbacks such as a lack of crack followability.

[Problem to be solved by the invention]

Therefore, the problem to be solved by the present invention is to develop a method for reducing the adhesiveness of urethane elastomer after application without affecting the pot life of the preparation or the physical properties of the produced elastomer, The object of the present invention is to provide a poor urethane elastomer.

[Means to solve the problem]

(Required Jl) In order to solve the above problems, the present invention comprises a urethane prepolymer (A) having terminal isocyanate groups, a compound having active hydrogen, and if necessary, a plasticizer, a catalyst, an antifoaming agent, a filler, etc. A urethane characterized by adding a drying oil in an amount of 0.1 to 5 ffL% to the mixture of (A) and (B) when mixing, reacting and curing the curing agent CB) containing the above. The gist is a method for reducing the tackiness of elastomers. Below, various matters related to the invention will be explained in terms of section. (Drying oil) Examples of the drying oil used in the present invention include vegetable oils and fats with an iodine value of 130 or more, such as linseed oil, tung oil, and eno oil. , these can be used alone or in combination of two or more. The above-mentioned drying oil can be added to the prepolymer and/or curing agent, or to a formulation of both, immediately before use. It is preferable to mix a drying oil into the agent; however, the present invention is not limited to the above-mentioned two-liquid type, but can also be used for a -liquid type, so in this case, the drying oil is Naturally, it is directly incorporated into the composition. The amount of drying oil added is determined by combining a urethane prepolymer (A) with terminal isocyanate groups, a curing agent (B) containing a compound having active hydrogen, and optionally a plasticizer, a catalyst, an antifoaming agent, a filler, etc. 0.1% by weight or more based on the total amount of
5! f! The amount added is preferably within the range of 0.1% by weight or less, the effect of improving adhesion is poor, and if it exceeds 5% by weight, a thick film of drying oil will form on the surface of the produced urethane elastomer. So I don't like it. (Other components) The urethane prepolymer having a terminal isocyanate used in the present invention contains an excess amount of isocyanates such as tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, and hexamethylene isocyanate in addition to a hydroxy compound such as polyether polyol. It is a reaction of Compounds having active hydrogen that are curing agent components include low molecular weight polyols such as ethylene glycol and butanediol, polyoxyalkylene glycols such as polyoxypropylene glycol, and 3.3°-dichloro-4,4° -Polyamines such as diaminodiphenylmethane can be mentioned. In addition to the above-mentioned main components, the following substances or materials can be exemplified as subcomponents that can be added as necessary, but of course they are not limited to only the exemplified ones. Plasticizers nidioctyl phthalate, dioctyl adipate, chlorinated paraffin, etc. Catalyst: lead octylate, dibutyltin dilaurate, etc. antifoaming silicone oil such as dimethylpolysiloxane;
Olefinic hydrocarbons such as polybutene. Fillers: Inorganic carbonates such as dicarbonate butycalcium, inorganic silicon compounds such as silica, and metal-resistant materials such as titanium oxide. Others: pigments, ultraviolet absorbers, anti-foaming agents, etc. In particular, one or more substances or materials are known as substances or materials added to cold-curing urethane elastomers used in civil engineering and construction applications.

[Effect]

When a urethane elastomer containing a drying oil is formed at a construction site according to the present invention, an extremely thin film of the drying oil that has been linoxinized by oxygen in the air covers the surface of the uncured elastomer layer. It is estimated that the surface tackiness disappears or decreases. Therefore, the higher the degree of unsaturation of the drying oil, the higher the tack-resolving effect.In addition, since the linoxinized film of the drying oil has excellent weather resistance, the weather resistance as a whole is further improved.

【Example】

Hereinafter, the embodiments and effects of the invention will be illustrated by Examples and Comparative Examples, but the examples are, of course, for illustrative purposes and are not intended to limit or limit the technical scope of the invention. Examples Urethane elastomer test pieces were prepared according to JIS A 602+ using the formulations shown in Table 1 below, and the IF value was determined. However, the curing agent must be prepared in advance (Ihalacyuamine% 7))
After 2) was dissolved in (Polyvar Dona T500)) 3), other raw materials were added thereto and mixed and dispersed. In addition, the following formulation is shown in 31 parts. (Space below) Table 1 Note 1) Trade name of urethane prepolymer manufactured by the applicant company (N
GO) containing i3.7$; 2) Trade name of 3,3゛-dichloro-4,4°-diaminodiphenylmethane manufactured by Ihara Chemical Industry ■; 3) Trade name of polyol manufactured by applicant company (hydroxyl value 35); 4. Trade name of curing catalyst made by Nippon Kagaku Sangyo. 5) No treatment according to JIS A 602+, measured value at 20"C. [1) Determined by palpating the surface of the urethane elastomer after 3 days at 20°C. As is clear from the above table, the samples to which the drying oil was added according to the present invention not only had no stickiness at all, but also showed better physical properties than the samples to which no additive was added.

【Effect of the invention】

As explained above, the present invention provides a method for reducing the tackiness of a urethane elastomer after application without affecting the pot life of the formulation or the physical properties of the produced elastomer, or a urethane elastomer with poor surface tackiness. By making it possible to provide an elastomer, it is possible to make a significant contribution not only to the field of civil engineering and construction, but also to the field of painting, where surface tackiness is undesirable. Patent applicant Daiichi Kogyo Seiyaku Co., Ltd.

Claims (1)

[Claims] Urethane prepolymer with terminal isocyanate groups (
When mixing A) and a curing agent (B) containing a compound having active hydrogen and, if necessary, a plasticizer, a catalyst, an antifoaming agent, a filler, etc., and reacting and curing the above (A) and (B).
A method for reducing the tackiness of a urethane elastomer, which comprises adding a drying oil in an amount of 0.1 to 5% by weight to the mixture.