JPH0834921A - Curing composition - Google Patents

Abstract

PURPOSE:To obtain a curing composition composed of a polysulfide polymer, an oxidizing agent, sulfur and a dithiocarbamic acid salt compound each in a specific amount, resistant to cracking by ozone irradiation, excellent in oil resistance, chemical resistance and fluidity and useful as a sealing material, etc. CONSTITUTION:This curing composition is composed of (A) a polysulfide polymer of 100 pts.wt., (B) an oxidizing agent such as ZnO2 of preferably 1-50 pts.wt. (C) sulfur of preferably 0.05-1 pts.wt. and (D) a dithiocarbamic acid salt compound such as N-pentamethylenedithiocarbamic acid zinc salt of 0.1-2 pts.wt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition, and more particularly to a curable composition suitable for use as a sealing material or the like which gives a cured product which is less likely to undergo crack deterioration due to ozone irradiation.

[0002]

2. Description of the Related Art A polymer containing two or more thiol groups in one molecule easily reacts with an oxidizing agent to have a high molecular weight and is widely used as a sealing material, a paint, an adhesive or the like. Among these thiol group-containing polymers, the polysulfide polymer described in U.S. Pat.No. 2,466,963 has excellent oil resistance, chemical resistance, flexibility and ozone resistance and is therefore used as a raw material for a sealing material. Came.

However, the polysulfide polymer itself has good ozone resistance, but when sulfur is added as a vulcanizing agent, it suffers from problems such as deterioration due to ozone irradiation and cracking.

[0004]

Therefore, an object of the present invention is to provide a curable composition suitable for use as a sealing material or the like, which gives a cured product which is unlikely to undergo crack deterioration due to ozone irradiation even when sulfur is added. Is to provide.

[0005]

As a result of earnest research in view of the above objects, the present inventors have found that polysulfide polymers are
The present invention was completed by discovering that cracking deterioration due to ozone irradiation can be suppressed by adding a predetermined amount of a dicarbamate compound together with an oxidizing agent and sulfur.

That is, the curable composition of the present invention comprises (A)
It is characterized by containing (B) an oxidizing agent, (C) sulfur, and (D) a dithiocarbamate salt compound in an amount of 0.1 to 2 parts by weight with respect to 100 parts by weight of a polysulfide polymer.

Hereinafter, the present invention will be described in detail. The curable composition of the present invention, (A) polysulfide polymer, (B)
An oxidant, (C) sulfur, (D) dithiocarbamate compound, and (E) other additives are blended as necessary. These components will be described below.

(A) Polysulfide polymer The polysulfide polymer in the curable composition of the present invention has the following general formula (1): HS (R ₁ S _x ) _m R ₁ SH (1) (where x is 1 to An integer of 5, m is an integer of 1 to 50, R ₁
Is an oxyalkylene group. The preferable range of x is 1 to 3, and the preferable range of m is 6 to 40. Preferred examples of the oxyalkylene group, -CH ₂ O
_{CH 2 -, - C 2 H} 4 OC 2 H 4 -, - C 2 H 4 OCH
_{2 OC 2 H 4 -, -} C 4 H 8 OC 4 H 8 - , and the like. ).

The above polysulfide polymer has fluidity at room temperature and preferably has a molecular weight of 100 to 200,000, more preferably 400 to 50,000. A preferred example of such a polysulfide polymer is US Pat.
It is described in No. 6,963.

(B) Oxidizing agent The substances conventionally used as a curing agent for thiol group-containing polymers can be used. Specific examples of these oxidizing agents include ZnO ₂ , FeO ₂ , PbO ₂ , MgO ₂ , and CaO.
₂ , BaO ₂ , MnO ₂ , TeO ₂ , SeO ₂ , Pb ₃
Inorganic peroxides such as O ₄ , SrO ₂ and LiO ₂ , ZnO,
FeO, PbO, Fe ₂ O ₃ , Sb ₂ O ₃ , MgO, C
Inorganic oxides such as oO, CaO, CuO, BaO, NaC
_{lO 4, NaBO 2 · H 2} O 2, K 2 C 2 O 6, KMn
O ₄ , inorganic oxidants such as sodium percarbonate, organic peroxides such as benzoyl peroxide, dicumyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, t-butyl perbenzoate, sodium peracetate and urea peroxide. Organic oxidants such as oxides, nitrobenzene, dinitrobenzene, and paraquinone dioxime can be used.
Of these, PbO ₂ is preferable.

The blending amount of these oxidizing agents varies depending on the kind of the oxidizing agent, but generally, polysulfide polymer 10
The amount is preferably 1 to 50 parts by weight, more preferably 1 to 30 parts by weight, based on 0 parts by weight. If the compounding amount is less than 1 part by weight, the curing is incomplete, and if it exceeds 50 parts by weight, the cured product becomes brittle, which is not preferable.

(C) Sulfur Sulfur is added as a vulcanizing agent. The content of sulfur is preferably 0.05 to 1 part by weight, more preferably 0.1 to 0.5 part by weight, based on 100 parts by weight of the polysulfide polymer.

(D) Dithiocarbamate compound As the dithiocarbamate compound,
(2):

(Wherein R ₂ and R ₃ are alkyl groups having 1 to 7 carbon atoms,
It is an alkylaryl group (for example, a benzyl group) or an alkylene group, R ₂ and R ₃ may be the same or different, n is an integer of 1 to 4, X is Zn, Ni, Na, Fe,
Cu, Pb, Se, Te, Bi, Cd, diethylamine, dibutylamine, piperidine, pipecoline, or ethylcyclohexylamine. ) Are preferred. When R ₂ and R ₃ are alkylene groups, R ₂ and R ₃ may be linked to each other to form a heterocyclic structure having 2 to 10 carbon atoms containing the N atom in the formula.

Specific examples of such dithiocarbamate compounds include zinc N-pentamethylenedithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, and zinc N-ethyl-N-phenyldithiocarbamate. , Zinc dibenzyldithiocarbamate, nickel diethyldithiocarbamate, nickel dibutyldithiocarbamate, sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, sodium dibutyldithiocarbamate, ferric dimethyldithiocarbamate, copper dimethyldithiocarbamate, lead dimethyldithiocarbamate, N -Lead pentamethylenedithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate , Bismuth dibutyldithiocarbamate, cadmium N-pentamethylenedithiocarbamate, diethylamine diethyldithiocarbamate,
Examples thereof include dibutylamine dibutyldithiocarbamate, piperidine N-pentamethylenedithiocarbamate, pipecoline methylpentamethylenedithiocarbamate, and ethylhexylamine N-cyclohexyldithiocarbamate. These dithiocarbamate compounds may be used alone or in combination of two or more.

The compounding amount of the dithiocarbamate compound is 0.1 with respect to 100 parts by weight of the polysulfide polymer.
It is 1 to 2 parts by weight, preferably 0.2 to 1 part by weight.
If the compounding amount of the dithiocarbamate compound is less than 0.1 part by weight, the effect of preventing crack deterioration due to ozone irradiation is insufficient, and if it exceeds 2 parts by weight, physical properties such as softening of the cured product are deteriorated, which is not preferable.

(E) Other Additives The curable composition of the present invention further has the following properties in order to improve economy, workability in applying the composition and physical properties after curing:
Fillers such as calcium carbonate, talc, clay, titanium oxide and silica can be added. Further, a phthalic acid ester such as butylbenzyl phthalate (BBP), a plasticizer such as chlorinated paraffin and hydrogenated terphenyl can also be added.

[0017]

The present invention will be described in more detail by the following examples. Examples 1 to 27 Polysulfide polymers ( Thiocol LP-55, manufactured by Toray Thiokol Co., Ltd.) were mixed with the types and blending amounts of plasticizers, fillers and the like shown in Table 1 to prepare a base A and a base B. A curing agent was prepared by mixing the types and amounts of the oxidizing agents and plasticizers shown in Table 2. Furthermore, the pigments, fillers and plasticizers of the types and amounts shown in Table 3 were mixed with the dithiocarbamate compounds of the types and amounts shown in Table 4 to obtain colorants. These main agents (types are shown in Table 4), a curing agent and a coloring agent were mixed to form a sheet having a thickness of 3 mm, and the sheet was cured by initial curing according to JIS A5758. Further, the obtained sheet-shaped cured product was subjected to an ozone resistance test in accordance with JIS A5758 to evaluate the presence or absence of softening and the occurrence of cracks. Table 4 shows the evaluation results.

Comparative Examples 1 to 14 Main ingredients (types are shown in Table 4) were prepared in the same manner as in Example 1 except that the type and amount of the dithiocarbamate compound in the colorant were changed as shown in Table 4. A curing agent and a coloring agent were blended to obtain a sheet-shaped cured product. Next, the ozone resistance of the sheet-shaped cured product obtained in the same manner as in Example 1 was evaluated. Table 4 shows the evaluation results.

Table 1 Main agent components Main agent A (parts by weight) Main agent B (parts by weight) Polysulfide polymer ⁽¹⁾ 100 100 Plasticizer ⁽²⁾ 74 65 Filler calcium carbonate 119 120 Titanium oxide 5 8 Physical property adjuster ⁽³⁾ 2 − Adhesiveness imparting agent ⁽⁴⁾ 0.2 0.1 Sulfur (vulcanizing agent) 0.3 0.5 Black pigment (carbon) − 0.5 Note (1): Thiokol LP-55, manufactured by Toray Thiokol Ltd. (2): Butylbenzyl phthalate (3) ): (Acrylic end) polyester urethane. (4): Silane coupling agent.

Table 2 Ingredient content of curing agent Oxidizer (lead dioxide) 7.5 parts by weight ⁽¹⁾ Plasticizer (chlorinated paraffin) 4.0 parts by weight Curing retarder (stearic acid) 0.5 parts by weight Note (1): Main agent The compounding amount is based on 100 parts by weight of the polysulfide polymer.

[0021] Table Ingredients Amounts of 3-color agent black pigment (carbon) 0.5 parts by weight ⁽¹⁾ blue pigment (Cyanine Blue) 0.03 parts by weight filler (titanium oxide) 8.0 parts by weight of plasticizer (butylbenzyl phthalate) 9.47 parts by weight Dithiocarbamate-based compound According to Table 4. Note (1): It is the compounding amount based on 100 parts by weight of the polysulfide polymer as the main ingredient.

Table 4 Examples of cracks in softening of dithiocarbamine ozone-resistant acid salt-based compounds NO. Main ingredient type Addition amount ⁽⁸⁾ Occurrence ⁽⁹⁾ Example 1 A DECZn ⁽¹⁾ 0.1 ◎ ○ Example 2 A DECZn 0.5 ◎ ◎ Example 3 A DECZn 1.0 ○ ◎ Example 4 A DECZn 1.5 ○ ◎ Example 5 A DBCZn ⁽²⁾ 0.1 ○ ○ Example 6 A DBCZn 0.5 ◎ ◎ Example 7 A DBCZn 1.0 ○ ◎ Example 8 A DBCZn 1.5 ○ ◎ Example 9 A PMCZn ⁽³⁾ 0.1 ◎ ○ Example 10 A PMCZn 0.5 ◎ ◎ Example 11 A PMCZn 1.0 ○ ◎ Example 12 A PMCZn 1.5 ○ ◎ Example 13 A DBCNi ⁽⁴⁾ 1.0 ○ ◎ Implementation Example 14 A DECNa ⁽⁵⁾ 1.0 ○ ◎ Example 15 A DMCCu ⁽⁶⁾ 1.0 ○ ◎ Example 16 A PMCP ⁽⁷⁾ 1.0 ○ ◎ Example 17 B DECZn 0.1 ◎ ○ Example 18 B DECZn 1.0 ○ ◎ Example 19 B DBCZn 0.1 ◎ ○ Example 20 B DBCZn 1.0 ○ ◎ Example 21 B PMCZn 0.1 ◎ ○ Example 22 BPMCZn 1.0 ○ ◎ Example 23 B PMCZn 1.5 ○ ◎ Example 24 B DBCNi 1.0 ○ ◎ Example 25 B DECNa 1.0 ○ ◎ Example 26 B DMCCu 1.0 ○ ◎ Example 27 B PMCP 1.0 ○ ◎ Comparative Example 1 A − − ◎ △ Comparative Example 2 A DECZn 0.05 ◎ △ Comparative Example 3 A DBCZn 0.05 ◎ △ Comparative Example 4 A PMCZn 0.05 ◎ △ Comparative Example 5 A DECZn 3.0 × ◎ Comparative Example 6 A DBCZn 3.0 × ◎ Comparative Example 7 A PMCZn 3.0 × ◎ Comparative Example 8 B − − ◎ △ Comparative Example 9 B DECZn 0.05 ◎ △ Comparative Example 10 B DBCZn 0.05 ◎ △ Comparative Example 11 B PMCZn 0.05 ◎ △ Comparative Example 12 B DECZn 3.0 × ◎ Comparative Example 13 B DBCZn 3.0 × ◎ Comparative Example 14 B PMCZn 3.0 × ◎ Note (1): Zinc diethyldithiocarbamate (2): Dibutyl Zinc dithiocarbamate (3): Zinc N-pentamethylenedithiocarbamate (4): Nickel dibutyldithiocarbamate (5): Sodium diethyldithiocarbamate (6): Copper dimethyldithiocarbamate (7): Pentamethylenedithiocarbamate piperidine salt (8): ◎: not softened, ○: slightly deteriorated in physical properties, ×: softened (9): ◎: no crack, ○: small crack, Δ: large crack, ×: fracture

As is clear from the results shown in the above table, since the cured product of the curable composition of the present invention has good ozone resistance, it may soften or generate cracks even when exposed to ozone. Absent.

[0024]

The curable composition of the present invention has a predetermined amount of a dithiocarbamate compound added to a polysulfide polymer together with an oxidizing agent and sulfur, so that a cured product obtained from the polysulfide polymer is cracked by ozone in the atmosphere. Hard to deteriorate. Such a curable composition is extremely suitable as a sealing material.

Claims (2)

[Claims] 1. A curing method comprising (A) 100 parts by weight of a polysulfide polymer, (B) an oxidizing agent, (C) sulfur, and (D) 0.1 to 2 parts by weight of a dithiocarbamate compound. Mold composition. 2. The curable composition according to claim 1, wherein the curing agent is 1 to 50 parts by weight and the sulfur is 0.05 to 1 parts by weight.