JPH0270749A - Curable composition - Google Patents

Abstract

PURPOSE:To obtain a curable composition of a decreased residual tack and a reduced tendency to be stained by adhesion of dust or rubber by adding a photosensitizer to a thiol-terminated polyether polymer. CONSTITUTION:This curable composition is formed by adding 0.05-10pts.wt. photosensitizer to 100pts.wt. thiol-terminated polyether polymer. Examples of the polyether polymer include polysulfide polymer of the formula, polyoxyalkylene polysulfide polymer, polyoxyalkylenepolymercaptan and poly(oxyalkylene)/polyester/poly(monosulfide) polythiol. The photosensitizers used are compounds which can be activated by light to generate radicals, such as photoinitiators usually used in ultraviolet-curable compositions, and are exemplified by benzoin isopropyl ether, benzoin isobutyl ether, benzophenone and benzil.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to curable compositions based on polyether polymers having terminal thiol groups.

(Prior art and problems to be solved by the invention) A polyether polymer having a thiol group at the end can be used as a sealant by utilizing the flexibility and flexibility due to its ether bond and the reactivity of the end thiol group. It is used in many fields of application as curable compositions such as adhesives. The form of these compositions is as follows: Immediately before use, a base containing a polyether polymer having a thiol group at the end is reacted with an oxidizing agent such as lead dioxide or an organic peroxide, or a thiol group such as an epoxy resin. Two-component type, in which two components of a curing agent containing a compound that causes a curing reaction are mixed and cured; and (2) a polyether polymer having a thiol group at the end and a curing catalyst are mixed in advance and placed in an airtight container such as a cartridge. There are two types: one-component type, which is stored, and when used, is taken out of the container and cured by oxygen, moisture, ultraviolet rays, etc. in the air.

The polyether polymer having a terminal thiol group used in the present invention can be obtained by various methods. Specific examples include polysulfide polymers represented by the general formula % described in U.S. Pat. No. 2,466,963, and U.S. Pat.
, 923,748 and Japanese Patent Publication No. 60-18687, polyoxyalkylene polymercaptans described in U.S. Pat. No. 3,258,495, U.S. Pat. No. 3,817,
There are polyether polymers having a thiol group at the end, such as poly(oxyalkylene)-polyester-poly(monosulfide) polythiol described in No. 936.

The photosensitizer used in the present invention is a photoactivator such as a photoinitiator normally used in ultraviolet curable compositions, etc.
Specific examples of compounds that generate radicals include benzoin isopropyl ether, benzoin isobutyl ether, benzophenone, benzyl, Michler's ketone, chlorothioxanthone, isopropylthioxanthone, benzyl dimethyl ketal, and hydroxycyclohexylphenyl ketone.

Compositions based on these polyethers with thiol groups at their ends have tack on the surface even after curing.
This has the drawback of causing dust and dirt to remain and impairing the appearance.

In order to improve the disadvantages of K, it has been empirically proven that plasticizers, waxes, etc. that are incompatible with these compositions are included in the composition, and the residual tack is reduced by their migration to the surface. It had been taken. However, plasticizers, wax, etc. that have migrated to the surface may migrate to the surrounding adherends and cause contamination, reduce adhesion to the adherend, and if paint is applied to the composition, the paint shi that reduced the adhesion with the
It contaminated the paint and had an adverse effect on other physical properties.

In addition, in the polyether polymer composition having hydrolyzable silicon groups used in the same dosage as the cured composition of the present invention, in order to reduce residual tack,
As described in No. 26349, a photocurable substance such as an unsaturated acrylic compound having a (meth)acrylic unsaturated group is added, and as described in JP-A-59-217757. Attempts have been made to add surfactants of the 7 series.

However, when a photocurable substance is added to the polyether polymer composition having a terminal thiol group according to the present invention, the residual tack can be reduced to some extent, but the viscosity of the composition increases during storage and the cured product becomes hard. It became brittle and had poor weather resistance, so it was not an effective solution.

Further, when a fluorine-based surfactant was added, there was no effect on reducing residual tack at all.

In view of the current situation, the present inventors conducted extensive research to reduce the residual tack of a curable composition based on a polyether polymer having a thiol group at the end, and as a result, the present invention was completed. .

Therefore, the purpose of the present invention is to significantly reduce residual tack, which is a drawback of conventional curable compositions based on polyether polymers having thiol groups at the ends, and to improve the problem of contamination caused by adhesion of dust and dirt. A curable composition is provided.

(Means and effects for solving the problems) The present invention provides a curable composition containing 0.05 to 10 parts by weight of a photosensitizer per 100 parts by weight of a polyether polymer having a thiol group at the end. It is related to.

The amount of photosensitizer to be blended is 0.05 to 10 parts by weight per 100 parts by weight of the polyether polymer having a thiol group at the end! The range is in parts. If the amount of photosensitizer is less than 0.05 parts by weight, residual tack will not be sufficiently reduced and a satisfactory effect will not be obtained. Further, even if the amount exceeds 10 parts by weight, the residual tack will not be reduced as much as in the formulation -3Llc, and on the contrary, it will easily cause discoloration such as yellowing and a decrease in weather resistance.

Various other components can also be added to the curable composition of the present invention. For example, fillers, pigments, viscosity modifiers,
Adhesive agents, antioxidants, ultraviolet absorbers, plasticizers, solvents, etc. can be added depending on the field of use of the composition.

(Effect of the invention) The curable composition of the present invention has significantly reduced residual tack,
The problem of contamination caused by adhesion of dust and dirt has been improved, and it can be effectively used in various applications such as adhesives, sealants, and adhesives.

(Examples) The present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Permapol P-965 (Nippon Shokubai Chemical Co., Ltd. trade name), which is a polyoxyalkylene polysulfide polymer as a polyether polymer having a thiol group at the end
were mixed according to the following formulation using 2-hydroxycyclohexylphenyl ketone as a photosensitizer to prepare a one-component oxygen-curable composition.

(Composition) Ingredients Permapol P-965 2-Hydroxycyclohexylphenylketone Calcium carbonate Titanium oxide diisodecyl heptalate Mixed xylene curing catalyst Ferric dimethyldithiocarbamate Zinc dibutyldithiocarbamate Part by weight 0.5 0.1 0. 3 After preparation, the obtained composition was filled into an aluminum container with a width of 10+ m, a depth of 10 m, and a length of 100 m, with the surface smoothed and placed on an outdoor exposure table. After 1 day, 3 days, 7 days, 28 days, and 3 months, the residual tack on the surface was evaluated by touch, and the degree of adhesion of dust and dirt was visually evaluated. Further, aluminum H-type test pieces were prepared from the obtained composition according to JIS A 5758, and tensile tests were conducted at the initial stage and after 3 months of outdoor exposure to evaluate weather resistance and adhesion.

The results are shown in Table 1, and the residual tack was completely gone after 3 days, and even after 3 months, the surface had an excellent appearance with very little dust and dirt attached. In addition, the tensile properties were high in elongation, and had good weather resistance and adhesion with little change due to exposure. ,.

Thiokol LP-32 (Toshi Thiokol ■ trade name), a polysulfide polymer represented by the general formula %, was mixed with benzophenone as a photosensitizer according to the following formulation to obtain two components. A mold curable composition was prepared.

(Composition) Ingredients Parts by weight (base) Thiokol LP-32100 Benzophenone 5 Calcium carbonate 60 Titanium oxide
15 Butyl benzyl 7 tallate 30 Stearic acid 1 Sulfur 0.1 Anti-aging agent 0.5 (manufactured by Tsukrak N5-5, Ohmukai wMσ ni 0) <Curing agent> Obtained after preparing lead dioxide butyl benzyl 7 tallate. Using the composition, residual tack, degree of adhesion of dust and dirt, and tensile properties were evaluated in the same manner as in Example 1. The results are shown in Table 1, and the residual tack did not completely disappear after 3 days, and even after 3 months, the surface had an excellent appearance with very little dust and dirt attached.

In addition, the tensile properties were high in elongation, and had good weather resistance and adhesion with little change due to exposure.

Comparative Example 1 In the formulation of Example 1, 2-hydroxycyclohexyl phenyl ketone was replaced with Aroex M-8060 (oligoester acrylate Toagosei Chemical Industry Co., Ltd.), which is an unsaturated acrylic compound that is a photocurable substance. A one-component oxygen-curable composition was prepared in the same manner, except that 5 parts by weight of 1.) and 1 part by weight of benzophenone were added.

The obtained composition was evaluated in the same manner as in Example 1. The results are shown in Table 1. Although there was a slight decrease in residual tack, the tensile properties were significantly lowered and the weather resistance and adhesiveness were poor.

Comparative Example 2 In place of 2-hydroxycyclohexylphenyl ketone in the formulation of Example 1, 0.5% of Unidyne DS 401 (per-70 loalkyl ethylene oxide adduct Daikin Industries @ trade name), a fluorosurfactant, was used. A one-component oxygen curable composition was prepared in the same manner except that part by weight was added.

The obtained composition was evaluated in the same manner as in Example 1. The results are shown in Table 1, and the residual tack was strong, and the surface of the cured product after 3 months had a lot of dust and dirt attached.

Comparative Example 3 A one-component type was prepared in the same manner as in Example 1, except that 1 part by weight of Osigard G (trade name of Yoro Kagaku Kogyo), a special wax, was added in place of 2-hydroxycyclohexylphenyl ketone. An oxygen curable composition was prepared.

The obtained composition was evaluated in the same manner as in Example 1. The results are shown in Table 1, and the residual tack was strong, and the surface of the cured product after 3 months had a lot of dust and dirt attached.

In addition, the tensile properties were inferior to the adhesive properties.

Comparative Example 4 A one-component oxygen curable composition was prepared in the same manner as in Example 1 except that 2-hydroxycyclohexylphenyl ketone was not added, and the same evaluation as in Example 1 was performed. The results are shown in Table 1, and the residual tack is strong.
There was also a lot of dust and dirt attached.

Comparative Example 5 A two-component curable composition was prepared in the same manner as in Example 2 except that benzophenone was not added, and the same evaluation as in Example 2 was performed. The results are shown in Table 1, and the residual tack was strong and there was a lot of dust and dirt attached.

Claims (1)

[Claims] 1. Polyether polymer 1 having a thiol group at the end
A curable composition containing 0.05 to 10 parts by weight of a photosensitizer per 0.00 parts by weight.