JPH03111432A - Production of foamed article - Google Patents

Abstract

PURPOSE:To facilitate the production of a foamed article of a satd. hydrocarbon polymer by condensing a curable compsn. comprising a satd. hydrocarbon polymer having a reactive, silicon group, a hydrated metal salt, and a silanol condensation catalyst, and utilizing a gas generated in the condensation as a blowing agent. CONSTITUTION:A curable compsn. comprising a satd. hydrocarbon polymer having hydroxyl or hydrolyzable groups directly attached to the silicon atoms and at least one silicon group capable of crosslinking by forming a siloxane bond [e.g. a hydrogenated polyisoprene of the formula, having a mol.wt. of about 2800, a viscosity of about 520P (20 deg.C), and silyl groups at its molecular terminals], a hydrated metal salt (e.g. Na2SO4.10H2O), and a silanol condensation catalyst (e.g. stannous octoate) is condensed, and a gas generated in the condensation is utilized as a blowing agent. Thus, a foamed article of the satd. hydrocarbon polymer is easily produced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing a hydrocarbon rubber foam.

Background Art and Problems to be Solved by the Invention It is generally known that saturated hydrocarbon rubbers have high gas barrier properties and excellent durability. Among them, IIR, which is made by copolymerizing inbutylene with a small amount of isoprene, is particularly
It is produced in large quantities for tire tubes.

However, there has been little research into methods for producing foams using isobutylene rubber such as ITR.

An object of the present invention is to provide a novel method for producing a saturated hydrocarbon polymer foam.

Means for Solving the Problems The present inventors have conducted intensive research to develop a new method for producing foams made of saturated hydrocarbon polymers, and as a result, the inventors have discovered that the hydroxyl groups or hydrolyzable groups bonded to silicon atoms have been a silicon atom-containing group that can be crosslinked by forming a siloxane bond (
It has been found that a foam can be easily obtained by using a saturated hydrocarbon polymer having at least one (hereinafter referred to as "reactive silicon group"). The present invention was completed based on this knowledge.

That is, the present invention provides a curable composition comprising (A) a saturated hydrocarbon polymer having at least one reactive silicon group, (B) a hydrate of a metal salt, and (C) a silanol condensation catalyst. The present invention relates to a method for producing a foam, which is characterized by condensing substances and using the gas generated during the condensation as a blowing agent.

In the present invention, component (A) is a saturated hydrocarbon polymer having at least one reactive silicon group.

Here, the reactive silicon group is not particularly limited, but representative examples include, for example, general formula (1) [wherein R1 and R2 are both alkyl having 1 to 20 carbon atoms] group, aryl group having 6 to 20 carbon atoms, 7 to 2 carbon atoms
0 aralkyl group or (R') 3 SiO-(R'
is a monovalent hydrocarbon group having 1 to 20 carbon atoms, and 3 R
' may be the same or different], and when two or more R1 or R2 are present, they may be the same,
May be different. X represents a hydroxyl group or a hydrolyzable group, and when two or more X's are present, they may be the same or different. a represents 011.2 or 3, and b represents 0.1 or 2, respectively. Moreover, b in m pieces does not need to be the same. m represents O or an integer of 1 to 19. However, the sum of a and b should satisfy ≧1. ] Groups represented by these can be mentioned.

The hydrolyzable group represented by X above is not particularly limited, and includes conventionally known hydrolyzable groups, specifically,
Examples include a hydrogen atom, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an aminooxy group, a mercapto group, and an alkenyloxy group. Among these, hydrogen atoms, alkoxy groups, acyloxy groups, ketoximate groups, amino groups, amido groups, aminooxy groups, mercapto groups, and alkenyloxy groups are preferred, and from the viewpoint of mild hydrolyzability and easy handling, alkoxy groups is particularly preferred.

The hydrolyzable group or hydroxyl group can be bonded to one silicon atom in the range of 1 to 3, and (the sum of a and b) is 1 to 5.
A range of is preferred. When two or more hydrolyzable groups or hydroxyl groups are bonded to a reactive silicon group, they may be the same or different.

The number of silicon atoms forming the reactive silicon group may be one,
The number may be two or more, but in the case of silicon atoms connected by siloxane bonds or the like, the number may be up to about 20. In particular, general formula (2) [wherein R2, X and a are the same as above. A reactive silicon group represented by the following is preferred from the viewpoint of easy availability.

Further, as specific examples of R1 and R2 in the above-mentioned formula (1), for example, an alkyl group such as a methyl group or an ethyl group,
Examples include cycloalkyl groups such as cyclohexyl groups, aryl groups such as phenyl groups, aralkyl groups such as benzyl groups, and triorganosiloxy groups represented by (R')3SiO-, where R/ is methyl group, phenyl group, etc. . Among these, methyl group is particularly preferred.

At least one reactive silicon group, preferably 1.1 to 5 reactive silicon groups, should be present in one molecule of the saturated hydrocarbon polymer.

When the number of reactive silicon groups contained in the molecule is less than one, the curability becomes insufficient.

The reactive silicon group may be present at the end of the saturated hydrocarbon polymer molecular chain, or may be present inside (or may be present on both sides).

The polymer forming the skeleton of the saturated hydrocarbon polymer having a reactive silicon group used as component (A) in the present invention is produced, for example, according to the method shown in (1) or (2) below.

(1) Ethylene, propylene, 1-butene, isobutylene, 2-butene, 2-methyl-1-butene, 3-methyl-1-butene, pentene, 4-methyl-1-pentene,
Polymerization is carried out using an olefin compound having 1 to 6 carbon atoms such as hexene or vinylcyclohexane as a main monomer. Here, the monomers may all be formed from the above-mentioned olefin compounds, and preferably 5 of the monomers include other monomers that are copolymerizable with the olefin compounds.
The content may be in the range of 0% by weight (hereinafter simply referred to as "%") or less, more preferably 30% or less, particularly preferably 10% or less. Examples of other monomers copolymerizable with olefin compounds include vinyl ethers, aromatic vinyl compounds, vinylsilanes, allylsilanes, and the like. Specific examples of such monomers include methyl vinyl ether, ethyl vinyl ether,
Examples include styrene, α-methylstyrene, vinyltrichlorosilane, vinylmethyldichlorosilane, allyltrichlorosilane, allyldimethylchlorosilane, and the like.

(2) Hydrogenating a homopolymer of a diene compound such as butadiene or isobutylene, or a copolymer of the above-mentioned olefin compound and a diene compound.

Even in the case of a polymer obtained by this method, monomer units derived from the other monomers may be present in the same proportion in the polymer.

In particular, ethylene-propylene copolymers, hydrogenated polyisoprene, and isobutylene-based polymers are preferred from the viewpoint of availability of raw materials and ease of handling.

The introduction of reactive silicon groups into the above saturated hydrocarbon polymer is as follows:
This may be carried out using a known method, for example, adding active groups and unsaturated groups that are reactive with the functional groups to a saturated hydrocarbon polymer having a functional group such as a hydroxyl group or an anhydride group at the end or in the main chain. The reaction product may be reacted with an organic compound having the following, and then the resulting reaction product may be hydrosilylated by acting on a hydrosilane having a hydrolyzable group. Among the above-mentioned isobutylene-based polymers having a reactive silicon group, isobutylene-based polymers having a reactive silicon group at the end of the molecular chain are produced by a polymerization method called the Vinifer method (using an initiator called an inifer and a chain transfer agent). It can be produced using a terminally functional type, preferably all terminally functional type isobutylene polymer obtained by a cationic polymerization method using a specific compound that also serves as a polymer. Such a manufacturing method is described, for example, in Japanese Patent Application Laid-Open Nos. 63-6041 and 63-6003.

The number average molecular weight of the saturated hydrocarbon polymer having reactive silicon groups is preferably about 500 to 30,000, particularly preferably about 1,000 to 15,000. In the present invention, such saturated hydrocarbon polymers may be used alone or in combination of two or more.

The saturated hydrocarbon polymer of component (^) releases low-molecular compounds produced by condensation during condensation, but this polymer has low gas permeability and is thought to produce foam. When carrying out the method of the invention, foams can be obtained even without the addition of blowing agents. Of course, other foams may be used in combination as long as the effects of the present invention are achieved.

The hydrate of the metal salt, which is the component (B) used in the present invention, acts as a source of moisture necessary for crosslinking the saturated hydrocarbon polymer having reactive silicon groups, which is the component (A). ,
It helps form a network structure. As such hydrates of metal salts, commercially available products can be widely used, such as hydrates of alkali metal salts, hydrates of alkali metal salts, hydrates of other metal salts, etc. It will be done. Specifically, AA'203 ・H2O, A1203113H20,
AJ2 (304)3 ・18H20, AA'2
(C20a) 3 ・4H20, A/Na
(SOa)2 ・12H20゜AA'K (So
, a) 2 ・ 12H20, BaC/2 @ 2
H20, B a (OH)2 ・8H20, CaO2 ・8H
20, CaSO3・2H20, CaSO4・2H201
CaS203 ・6H20, Ca (NO3)2 ・4H20, CaHPO4・
2H20, Ca (C204)・H20, CO(N03)2116H20, co (CH3C00)2 ・4H20, CuCl2
” 2H20, CuSO4' 5H20, FeCl2
・4H20, F e CA' e ・6 H20%F
eSO4・7H20, Fe (NH4) (804)2 ・12H20
, K2CO3・1.5H20, KNaC03・6H20, L i B r ・2 H2
0% Li2SO4.H2O, MgSO4.H2O.

MgSO4・7H20, Mg HP Oa・7H
20, Mg3 (PO4)2 ・8H20゜MgCO
3・3H20, Mga (CO3) 3 (OH)2 ・3H20
, MOO3・2H20, NaBr・2H20, Na2
803 Φ7H20, Na2 SO4・10H20, Na2 S203 ・5H201 Na2 S206 ・2H201 NaHPHO3” 2. 5H20, Na3 PO
4. 12H20, NaH2PO4.2H20゜Na2 CO3.H201Na2 CO3.7H20,
Na2 CO3・10H20, NaCH3COO・3H201 NaHC204・H20, NiSO4・6H201Ni
C204・2H2015n02・nH20,Sn
(SO4)2 ・2H20%ZnSO3・2H20,
ZnSO4・7H201Zn3 (PO4)2 ・
Examples include, but are not limited to, 4H20, Zn(CH3C00)2.2H20, and the like.

Among these, hydrates of alkali metal salts and hydrates of alkaline earth metal salts are preferred, specifically CaO2.
8H20, Ca5Oa ” 2H20゜M g SO
a・7H20, Na2SO4・10H20, N82CO3''10H20, etc.

The blending ratio of component (A) and component (B) is not particularly limited and can be appropriately selected within a wide range.
B) The number of water molecules in the hydrate of the metal salt of component is 0.3 to 10
It is preferable to mix them in proportions that are approximately equal to each other.

As the silanol condensation catalyst used as component (C) in the present invention, a wide variety of conventionally known catalysts can be used. Specific examples include titanate esters such as tetrabutyl titanate and tetrapropyl titanate; tin carboxylates such as dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, tin octylate, and tin naphthenate; dibutyltin oxide and phthalic acid. Reactant with ester; dibutyltin diacetylacetonate; aluminum trisacetylacetonate,
Organoaluminum compounds such as aluminum trisethyl acetoacetate and diisopropoxyaluminum ethylacetoacetate; chelate compounds such as zirconium tetraacetylacetonate and titanium tetraacetylacetonate; lead octylate; butylamine, octylamine, dibutylamine, mono Ethanolamine, jetanolamine, triethanolamine, diethylenetriamine, triethylenetetramine, oleylamine, cyclohexylamine, benzylamine, diethylaminopropylamine, xylylenediamine, triethylenediamine, guanidine, diphenylguanidine, 2,
4.6-1 lis(dimethylaminomethyl)phenol,
Morpholine, N-methylmorpholine, 2-ethyl-4-
Methylimidazole, 1,8-diazabicyclo(5,4
,0) amine compounds such as undecene-7 (DBU),
Or salts with these carboxylic acids, etc.; low molecular weight polyamide resins obtained from excess polyamines and polybasic acids; reaction products between excess polyamines and epoxy compounds; silane coupling agents having amino groups, such as γ- Examples include silanol condensation catalysts such as aminopropyltrimethoxysilane and N-(β-aminoethyl)aminopropylmethyldimethoxysilane, as well as other known silanol condensation catalysts such as acidic catalysts and basic catalysts.

These catalysts may be used alone or in combination of two or more. The blending amount of component (C) is preferably about 0.1 to 20 parts, more preferably about 1 to 10 parts, per 100 parts by weight (hereinafter simply referred to as "parts") of component (A). (A)
If the amount of the silanol condensation catalyst blended with respect to the components is too small, the curing speed of the resulting resin composition will be slow, while if it is too large, the physical properties such as the tensile properties of the resulting foam will deteriorate, so both are unfavorable.

The composition of the present invention further includes a plasticizer, an adhesion improver, a physical property adjuster, a storage stability improver, a filler, a sulfur-based anti-aging agent, an ultraviolet absorber, a metal deactivator, an ozone deterioration agent, etc. Various additives such as inhibitors, light stabilizers, amine-based radical chain inhibitors, phosphorus-based peroxide decomposers, lubricants, pigments, and blowing agents can be added as appropriate.

When the above-mentioned curable resin composition is cured for 6 minutes to 10 days at a temperature sufficient for the low molecular weight compound produced by condensation to vaporize and contribute to foaming, for example, 20 to 120°C, a rubber foam can be obtained. I can do it.

This product is a saturated hydrocarbon rubber with outstanding weather resistance, heat resistance, water resistance, moisture barrier properties, strength, elongation properties, etc., and because it is a foam, it is suitable for automotive weather protection. It can be used in a wide variety of applications, including strips, building sealants, packing materials, and vibration-proofing materials.

Furthermore, since the polymer used as component (A) in the present invention contains a reactive silicon group, it can be applied to various adherends such as glass, aluminum, natural rubber, butyl rubber, epoxy resin, acrylic resin, and vinyl chloride resin. It can be adhered to various base materials such as , nylon, and galvanized iron, and has good water-resistant adhesion, heat-resistant adhesion, etc.

The expansion ratio of the present foam can be controlled by changing the curing temperature. By increasing the curing temperature, the foaming ratio can be increased.

Effects of the Invention According to the manufacturing method of the present invention, a foam can be easily obtained.

Example In order to further clarify the present invention, Examples are listed below.

Examples 1 to 6 The molecular weight is approximately 2800, and the viscosity is approximately 520.
To 100 parts of a hydrogenated polyisoprene polymer having a silyl group at the end of Poise (20°C), hydrated metal salts, fillers, and plasticizers were added as shown in Table 1, and the mixture was applied to three paint rolls. , and kneaded three times. Further, 3 parts of tin di-n-octylate and 0.75 parts of laurylamine were added to this, stirred, poured into a mold with a thickness of 40 mm, and heated at 80°C for 10 minutes.
A foam was easily obtained by aging for a period of time.

Examples 7 to 12 100 parts of the hydrogenated polyisoprene polymer of Example 1 was converted into a polymer having a molecular weight of about 5400 and a viscosity of about 610.
The same procedure as in Examples 1 to 6 was carried out except that 100 parts of polyisobutylene having a silyl group at the end having a temperature of 0 poise (20 DEG C.) was used, and the results are shown in Table 2.

Claims (1)

[Scope of Claims] [1] (A) A saturated hydrocarbon system having a hydroxyl group or a hydrolyzable group bonded to a silicon atom and having at least one silicon atom-containing group that can be crosslinked by forming a siloxane bond. A foamed product characterized by condensing a curable composition containing a polymer, (B) a hydrate of a metal salt, and (C) a silanol condensation catalyst, and using the gas generated during the condensation as a blowing agent. manufacturing method. [2] The method for producing a foam according to claim [1], wherein the saturated hydrocarbon polymer as component (A) has a number average molecular weight of 1,000 to 15,000. [3] Claim [1] wherein the hydrate of the metal salt as component (B) is at least one selected from the group consisting of hydrates of alkali metal salts and hydrates of alkaline earth metal salts. Method of manufacturing the foam described.