JPS62285971A - Sealant composition - Google Patents

Abstract

PURPOSE:To impart curability which is hardly affected by ambient temp., to prolong a pot life and to improve adhesion, by using a catalyst mixture of a lead catalyst and a tin catalyst in a specified molar ratio in preparing polyurethane sealing materials other than those of one-pack type. CONSTITUTION:A polyurethane prepolymer (A) mainly composed of a polyol (e.g., polyethylene glycol) and a polyisocyanate (e.g., tolylene diisocyanate) is combined with a curing catalyst (B) obtd. by mixing a lead catalyst with a tin catalyst in a molar ratio of lead to tin of 30:1-1.2:1 to obtain a sealant compsn. for polyurethane sealing materials other than those of one-pack type. Examples of the lead catalyst are lead caprylate, lead naphthenate, etc. Examples of the tin catalyst are dibutyltin dilaurate, tin caprylate, etc.

Description

Detailed Description of the Invention 3. Technical Field of the Invention The present invention relates to a polyurethane sealant composition, particularly a sealant composition that is less susceptible to environmental temperature effects in curability and has good physical properties and workability. Regarding.

<Prior Art> A sealant is a material used for the purpose of preventing leakage of water or air, or for preventing dust.

The basic composition of a two-component polyurethane sealing material using a polyurethane resin is a urethane prepolymer as the main ingredient, a 1. It consists of a mixture of polyols, plasticizers, fillers, catalysts, anti-aging agents, etc. Conventionally, among such raw materials for curing agent compositions, lead-based catalysts such as lead octylate have been used alone as catalysts.

However, the use of lead-based catalysts such as lead octylate-based catalysts has the problem that curing properties are easily affected by environmental temperature, and significant differences in physical properties and workability occur depending on the environmental temperature.

Furthermore, tin-based catalysts such as dibutyltin dilaurate have poor curability when used alone.

Also, problems remain in terms of surface tack, slump, and foaming, making it unusable.

<Object of the Invention> The object of the present invention is to solve the above-mentioned problems in the prior art, and to provide a polyurethane sealant composition whose curability is less affected by environmental temperature, has a long pot life, and has good adhesive properties. It's about doing.

<Structure of the Invention> The present invention is a polyurethane sealing material other than a l-liquid type, in which a lead-based catalyst and a tin-based catalyst are used as catalysts in a molar ratio of lead to tin of 30:1 to 1.2: Provided is a sealant composition comprising: 1.

The present invention will be explained in detail below.

The present invention is a polyurethane resin other than molding, typically a two-component type, and is characterized by the catalyst used.

Typical examples of the lead-based catalyst of the present invention include lead octylate and lead naphthenate. Typical examples of the tin-based catalyst include dibutyltin dilaurate and tin octylate.

The feature of the present invention is that a tin-based catalyst is used in combination with a lead-based catalyst that was conventionally used alone, and the ratio of the lead-based catalyst and the tin-based catalyst is
The molar ratio of lead to tin is 30:1 to 1.2:1. If it is less than 1.2:1, foaming or slump will occur, and if it exceeds 30:1, the effect of the tin-based catalyst will be reduced.

The composition of the polyurethane resin used in the present invention consists of a urethane polypremer and a curing agent.
It is preferable to include additives (anti-sagging agents, fillers, plasticizers, light stabilizers, etc.).

The main components of the urethane prepolymer are polyol and polyisocyanate.

Polyols used in the present invention include polyether polyols such as polytetramethylene glycol, polyethylene glycol, and polypropylene glycol, olefin polyols such as polybutadiene polyol and polyisoprene polyol, adipate polyols, lactone polyols, and mustard oil. Polyester polyols such as can be used. Moreover, several kinds of these polyols can be combined as necessary.

Polyisocyanates include tolylene diisocyanate,
Diphenylmethane 4,4'-diisocyanate and its modified products, 1,5-naphthylene diisocyanate, bitolylene diisocyanate, infronnoincyanate, xylene diisocyanate, etc. can be used.

Usually, the urethane polymer is obtained by reacting the polyisocyanate/(polyol) in an equivalent ratio of 4/l to 2.5/1, preferably 1.871 to 2.2/1.

Preferred examples of the plasticizer include phthalate ester plasticizers such as dioctyl phthalate and dibutyl phthalate, and fatty acid ester plasticizers such as dioctyl adipate and dioctyl sebacate.

<Example> This will be specifically explained below using examples.

Example 1 Hardening agent compounds were prepared using the formulations listed in Table 1.
■Created.

Example (2) is an example of the present invention using lead octylate and dibutyltin silacrate as catalysts.

(2) and (2) are comparative examples in which lead-based catalysts and tin-based catalysts were used alone as catalysts, respectively.

(2) was used as a comparative example with the ratio of lead-based catalyst: tin-based catalyst outside the range. 100 parts of polymer and 300 parts of curing agent compounds (1) to (2) shown in Table 1 were mixed at 20°C and cured as a sealant composition.

The following trial was conducted and the results are shown in Table 2.

(+) Slump test A sag test in a sealant temperature environment (50°C) according to JIS A3758 Section 5.3, expressed as sag length.

(2) Surface tack test Test by finger touch after 71 days at 20°C.

(3) Curability test After 7 days at 20°C, check the cured state by touch.

(1) Foaming test A vinyl chloride cylinder with a diameter of 10 m/+++ length of 50 m/In was filled with sealant, and the extent to which it filled the cylinder after curing was examined.

Table 1 * 201% as lead content Unit weight component 18wt% as tin content Table 2 Composition Unit weight part i As shown in Table 2, when hardener compounds m and ■ are used, slump, surface tack, hardenability and foaming properties are reduced. There is a problem, but no problem is seen with curing agent compound (2).

Example 2 An adhesion test was conducted using the sealant composition shown in Table 2. The adhesion test was conducted according to JIS 85758.

Covering body: mortar board Primer Coprimer No. 30 (manufactured by Yokohama Rubber) Curing conditions: Pre-curing standard condition 7 days Post-curing: 50±3℃ for 7 days Test conditions: (1) Standard condition 7 days + 50 ± 3°C 7 days later test (2) (1) + 20±3℃ water immersion for 7 days? wheat test (3) (1) +80±3℃ 14 days T & test The results are shown in Table 3.

Table 3] As shown in Table 3, the comparative examples using curing agent compounds m and 2 had poor curing properties and could not be stretched.

The inventive example using curing agent compound (■) showed an increase in adhesion compared to the comparative example using T.

In addition, the pot life of the inventive example was about 6 hours, which was 2 hours longer than that of the comparative example (1).

<Effects of the Invention> The sealant composition of the present invention uses a lead-based catalyst and a tin-based catalyst in a specific ratio as catalysts for polyurethane resin, and has the following effects.

■ Curability is less affected by environmental temperature.

■　Surface tack is reduced.

■ Longer pot life.

■ Adhesion is improved.

Claims (1)

[Claims] (1) A polyurethane sealing material other than a one-component type, which contains a lead-based catalyst and a tin-based catalyst as catalysts at a molar ratio of lead to tin of 30:1 to 1.2:1. A sealant composition characterized by: