JPH07268215A - Curable composition - Google Patents

Abstract

PURPOSE:To obtain a curable composition suitable for a sealing material that gives a joint with controlled staining by mixing a polymer having at least two terminal thiol groups (e.g. polysulfide), a curing agent comprising MnO2. an adsorbent comprising a specified compound, and an oxidizing agent. CONSTITUTION:This composition is produced by mixing 100 pts.wt. polymer having at least two terminal thiol groups (e.g. polysulfide or thiol-containing polyether) with 0.5-50 pts.wt. curing agent comprising MnO2, 0.01-50 pts.wt. adsorbent and/or 0.01-50 pts.wt. oxidizing agent. As the adsorbent, both of a chemical adsorbent and a physical adsorbent can be used; however, tetrasodium ethylenediaminetetraacetate is particularly desirable. As the oxidizing agent, CuO is preferably used in particular. When this composition is applied as a sealing material, the occurrence of dark brown stains due to MnO2 at the joint part of concrete, etc., can be controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition which is cured by the reaction of MnO ₂ and a thiol group, and more particularly to a curable composition which markedly suppresses contamination of construction joints and can be used as a sealing material.

[0002]

2. Description of the Related Art A polymer having two or more thiol groups in one molecule is easily cured if it is not mixed with an oxidizing agent, and the thiol group easily reacts with an epoxy group, an isocyanate group or the like to have a high molecular weight. Therefore, it is widely used in sealing materials, paints, and adhesives.

Inorganic oxides, inorganic peroxides, organic peroxides and the like are known as oxidizing agents for these thiol group-containing polymers, and generally PbO ₂ , MnO ₂ and Zn are known.
Metal oxides such as O ₂ and CaO ₂ are widely used.

[0004]

The thiol group-containing polymer, when cured with MnO ₂ , is easily cured and exhibits good physical properties. However, there is a problem that when it is applied to the outdoor part, the dark brown contamination gradually occurs on the joint part such as concrete.

Accordingly, it is an object of the present invention to provide a curable composition which does not contaminate joints such as concrete even when it is applied outdoors when a thiol group-containing polymer is cured using MnO _2. Is.

[0006]

As a result of earnest research on the above object, the present inventor has found that a polymer containing a thiol group such as a polysulfide polymer is used as a curing agent for MnO ₂
At the same time, they have found that the addition of a specific compound makes it possible to obtain a curable composition that does not contaminate joints such as concrete even when it is constructed outdoors, and conceived the present invention.

That is, the curable composition of the present invention comprises (1)
Polymer 1 having at least two thiol groups at the end
(2) 0.5 to 50 parts by weight of (2) MnO ₂ and (3) 0.01 to 50 parts by weight of an adsorbent and / or 0.01 to 50 parts by weight of an oxidizer per 100 parts by weight of Is characterized by.

The present invention will be described in detail below. The curable composition of the present invention comprises (1) 100 parts by weight of a polymer having at least two thiol groups at the ends, and (2) Mn.
O ₂ 0.5 to 50 parts by weight, and (3) adsorbent 0.01 to 50
It is a composition with 0.01 to 50 parts by weight of an oxidizing agent.

[1] Thiol Group-Containing Polymer Examples of the thiol group-containing polymer used in the present invention include polysulfide polymers described in US Pat. No. 2,466,963 and thiol group-containing polyether polymers described in Japanese Patent Publication No. 47-48279. And the polysulfide polyether polymer described in JP-A-4-363325.

Other known polymers include US Pat.
Liquid polymer described in US Pat. No. 3,923,748, US Pat.
And polymer captans described in JP-B-46-3389. A general formula representing an example of a preferable thiol group-containing polymer is shown below.

[Chemical 1] However, p is an integer of 0 to 25, and q, r, s, t, and u are 2
Is an integer of -100, v is an integer of 0-50, z is an integer of 1-4, and R is hydrogen or a methyl group.

[2] MnO ₂ MnO ₂ may be used as a curing agent for a conventional curable composition. In the composition of the present invention, the compounding amount of MnO ₂ is preferably 0.1 to 50 parts by weight with respect to 100 parts by weight of the thiol group-containing polymer. MnO ₂
If the blending amount is less than 0.1 part, the curing of the (1) thiol group-containing polymer will be insufficient, and if it exceeds 50 parts by weight, it is economically undesirable.

[3] Adsorbent and / or Oxidizing Agent (a) Adsorbent The adsorbent is a metal compound, a compound having a so-called chemisorption property for adsorbing and holding a metal or a metal ion by a chemical bonding force, or Van der Any compound can be used as long as it has a so-called physical adsorption property of being adsorbed and held by the Waals force. A cation exchanger or a chelating reagent can be used as the adsorbent by the chemical bond. Examples of the cation exchanger include synthetic resins having a sulfonic acid group, an acidic hydroxyl group or a carboxyl group introduced as an ion exchange group. Specific examples of the chelating agent include ethylenediaminetetraacetic acid (EDTA), triethylenetetraminehexaacetic acid (TTHA), diethylenetriaminepentaacetic acid (DTPA), nitrilotriacetic acid (NTA).
And various sodium salts thereof, various chelating agents such as uramil (UDA), and iminodiacetic acid (-N (CH ₂
COO ^-) _2), a polyamine (-NH (CH ₂ CH ₂ N
H) _n · H) and other synthetic resins (chelate resins) into which a chelate-forming group is introduced. Among them, it is particularly preferable to use the tetrasodium salt of ethylenediaminetetraacetic acid.

Specific examples of the adsorbent that physically adsorbs are synthetic adsorbents having an aromatic (styrene-divinylbenzene) type and an acrylic (methacryl) type as a chemical base, and an adsorbing property such as acid clay or activated clay. Clay minerals, various zeolites, activated alumina, etc. can be used.

(B) Oxidizing agent As the oxidizing agent, a substance used as a conventional curing agent for a thiol group-containing polymer can be used. Specific examples thereof include inorganic peroxides such as FeO ₂ , PbO ₂ and ZnO ₂ , inorganic oxides such as CuO, CaO, BaO and Sb ₂ O ₃ , Na ₂ CrO ₄ , NaBO ₃ .4H ₂ O, KMn
Inorganic oxidizers such as O ₄ , sodium percarbonate (2Na ₂ CO ₃ + 3H ₂ O ₂ ), organic peroxides such as sodium peracetate, benzoyl peroxide, urea peroxide, etc., organic oxidation such as nitrobenzene, paraquinone dioxime, etc. Agents. Among them, it is particularly preferable to use copper (II) oxide (CuO).

Any one of the above adsorbents and oxidants may be used, or the adsorbents and oxidants may be used in combination. When an adsorbent and an oxidizing agent are used in combination, a combination of a tetrasodium salt of ethylenediaminetetraacetic acid as the adsorbing agent and copper (II) oxide as the oxidizing agent is particularly preferable. When either an adsorbent or an oxidant is used, the compounding amount of the specific substance (3) (a) adsorbent or (b) oxidant in the composition of the present invention is (1) thiol group-containing polymer 100.
It is preferably 0.1 to 50 parts by weight with respect to parts by weight. When a combination of (a) an adsorbent and (b) an oxidant is used, the specific substance (3) in the composition of the present invention
The blending amount of ((a) + (b)) is 0.2 to 100 parts by weight relative to 100 parts by weight of the thiol group-containing polymer (1), and the blending amounts of (a) and (b) are both 0. It is preferably 1 to 50 parts by weight. If the blending amount of (a) and (b) is less than 0.1 parts by weight, the effect of suppressing contamination around the construction joint is poor, and if it exceeds 50 parts by weight, it is economically unfavorable.

(C) Other Additives In the curable composition of the present invention, for the purpose of further improving economy, workability in applying the composition and physical properties after curing,
Fillers such as calcium carbonate, talc, clay, titanium oxide, and silica, and plasticizers, adhesion promoters, vulcanization accelerators, and other materials used for ordinary thiol group-containing polymer cured products can be added.

[0017]

When the thiol group-containing polymer is cured with MnO ₂ , it is easily cured and exhibits good physical properties. However, when it is constructed in the outdoor area, it gradually causes dark brown contamination on the joints such as concrete. In the present invention, by adding an adsorbent and / or an oxidant together with MnO _{2 as} a curing agent to a thiol group-containing polymer, even when it is constructed outdoors, contamination at joints such as concrete is prevented. Can be effectively suppressed.

The reason why such an effect is obtained is not necessarily clear, but an adsorbent having chemical and physical adsorption performance adsorbs a water-soluble Mn compound which is considered to be a cause of pollution, so that rainwater or the like may be used. It is considered that pollutants suppress the outflow from the hardened material to concrete.
Similarly, the effect of adding an oxidizing agent is not always clear, but it is considered that the water-soluble Mn compound generated by the reaction with the thiol group is oxidized into MnO ₂ which is hardly soluble in water.

[0019]

The present invention will be described in more detail based on the following examples, but it goes without saying that these do not limit the scope of the present invention.

Examples 1 to 12 and Comparative Example 1 Polysulfide polymer (Toray Thiokol Ltd., trade name "Thiocol LP55"), a plasticizer, a filler, and a specific compound (3) of the present invention shown in Table 3 Of these, the adsorbent (a) was blended in the proportions shown in Table 1 to obtain the main agent A. Also, M
Curing agent A was obtained by mixing nO ₂ with a plasticizer and a filler in the proportions shown in Table 2. In addition, among the specific compounds (3), the main agent in which (a) the adsorbent was not mixed was used as Comparative Example 1.

Hardener A was mixed with the main agent thus obtained, and a mortar piece of 20 mm × 50 mm × 50 mm (JIS R 52
5 mm x 25 mm) manufactured according to 0l, 9.4)
It was applied at × 50 mm and exposed outdoors. For this test piece, the state of contamination around the coated surface after 1 month was observed,
Those with no black-brown contamination are ◎, those with almost no contamination are ○,
Those having a suspicion of contamination are indicated by Δ, and those apparently contaminated are indicated by ×, and the results are shown in Table 3.

Table 1 Mixing ratio of main agent Compounding agent Examples 1 to 12 Comparative example 1 Polysulfide polymer (Thiocol LP55) 100 100 Plasticizer (butylbenzyl phthalate) 74 74 Filler (calcium carbonate) 112.8 117.8 Filler (Titanium oxide) 55 Adsorbent 50 Note: The numerical values in the table indicate parts by weight when the thiol group-containing polymer is 100 parts by weight.

Table 2 Compounding ratio of curing agent A Compounding agent Weight part MnO ₂ 10 Plasticizer (chlorinated paraffin) 12 Additive (tetrathiuram disulfide) 0.3 Note: The values in the table are 100 weight of the thiol group-containing polymer. The parts by weight are shown.

Table 3 Types of adsorbents and experimental results No. Type of adsorbent Contamination state Example 1 Triethylenetetramine hexaacetic acid hexasodium salt ⁽¹⁾ △ Example 2 Diethylenetriamine pentaacetic acid △ Example 3 Diethylenetriamine pentaacetic acid pentasodium salt ⁽²⁾ △ Example 4 Ethylenediaminetetraacetic acid ○ ~ △ Example 5 Ethylenediaminetetraacetic acid disodium salt ⁽³⁾ ○ ~ △ Example 6 Ethylenediaminetetraacetic acid trisodium salt ⁽⁴⁾ ○ ~ △ Example 7 Ethylenediaminetetraacetic acid tetrasodium salt ⁽⁵⁾ ○ Example 8 Iminodiacetic acid type chelate resin △ Example 9 Polyamine type chelate resin △ Example 10 Sulfonic acid type ion exchange resin △ Example 11 Activated clay △ Example 12 Activated alumina △ Comparative example 1 None × Note: (1)

[Chemical 2] (2)

[Chemical 3] (3)

[Chemical 4] (4)

[Chemical 5] (5)

[Chemical 6]

Examples 13 to 18 and Comparative Examples 2 and 3 The oxidizing agent, the plasticizer and the filler were blended in the proportions shown in Table 4 to obtain the oxidizing agent B1 and the oxidizing agent B2, respectively. Examples 13 and 1
In Example 4, the main agent, curing agent A and oxidizing agent B1 used in Comparative Example 1 were used, and in Examples 15 and 16, the main agent, curing agent A and oxidizing agent B2 used in Comparative Example 1 were used, and Example 17 was used.
Then, the main agent, curing agent A and oxidizing agent B used in Example 7 were used.
In Example 18, in Example 18, the main agent and the curing agent A used in Example 7 were mixed in the proportions shown in Table 5, and the mixture was applied to mortar pieces in the same manner as in Examples 1 to 12. The state of contamination of the coated surface after one month was observed. The results are also shown in Table 5. In Comparative Examples 2 and 3, the main agent used in Comparative Example 1 and the curing agent having the MnO ₂ amount in the curing agent A shown in Table 5 were used, and the main agent and the curing agent were mixed and the same evaluation was performed. The results are also shown in Table 5.

Table 4 Mixing Ratio of Oxidizing Agent Oxidizing Agent Name Oxidizing Agent B1 Oxidizing Agent B2 CuO ZnO ₂ Oxidizing Agent 10 10 Plasticizer (Chlorinated Paraffin) 5 5 Filler (Titanium Oxide) 10 10 Note: The values in the table are Parts by weight are shown.

Table 5 Mixing ratio of curable composition and experimental results Curing agent A Oxidizing agent B1 Oxidizing agent B2 Adsorbent Example No. MnO ₂ CuO ZnO ₂ EDTA · 4Na Contamination state Example 13 5 2 0 0 △ Example 14 2 5 0 0 ○ Example 15 5 0 2 0 △ Example 16 2 0 5 0 ○ Example 17 5 2 0 5 5 ◎ Example 18 5 0 0 5 ○ Comparative Example 2 5 0 0 0 × Comparative Example 3 2 0 0 0 Δ Note: The numerical values in the table indicate parts by weight when the thiol group-containing polymer is 100 parts by weight.

As is clear from Tables 3 and 5, the curable composition of the present invention has little pollution and can be used outdoors.

[0029]

As described in detail above, since the curable composition of the present invention contains a thiol group-containing polymer and MnO _{2 as} a curing agent, an adsorbent and / or an oxidant,
Even when it is constructed outdoors, it is possible to effectively suppress the occurrence of pollution at joints such as concrete.

Claims (3)

[Claims] 1. (1) 0.5 to 50 parts by weight of MnO ₂ , and (3) 0.01 to 50 parts of an adsorbent, relative to 100 parts by weight of a polymer having at least two thiol groups at the ends. A curable composition comprising 0.01 part by weight and / or 0.01 to 50 parts by weight of an oxidizing agent. 2. The curable composition according to claim 1, wherein the adsorbent is a tetrasodium salt of ethylenediaminetetraacetic acid. 3. The curable composition according to claim 1, wherein the oxidizing agent is copper (II) oxide.