JP2007131750A - Addition curing type organopolysiloxane composition and method for promoting curing thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To promote curing during curing use while maintaining long-term preservation stability of an addition curing type organopolysiloxane composition. <P>SOLUTION: The addition curing type organopolysiloxane composition comprises (A) an organopolysiloxane containing average ≥2 alkenyl groups bonded to silicon atom in one molecule, (B) an organohydrogenpolysiloxane containing at least ≥2 hydrogen atoms bonded to silicon atom in one molecule in an amount so as to provide 0.5-5.0 number of hydrogen atoms bonded to the silicon atom contained in one molecule of the component (B) based on one alkenyl group possessed by the organopolysiloxane of the component (A), (C) a catalytic amount of a catalyst for a hydrosilylating reaction, (D) a reaction controller and (E) a curing promoter having at least one carboxy group in one molecule. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an addition-curable organopolysiloxane composition comprising a curing accelerator for a platinum-catalyzed addition reaction between an organopolysiloxane having an aliphatic unsaturated group and an organopolysiloxane having a hydrogen atom bonded to a silicon atom, and The present invention relates to a method for promoting the curing.

  Conventionally, an organohydrogenpolysiloxane having a hydrogen atom (SiH) bonded to a silicon atom, an organopolysiloxane having an alkenyl group such as a vinyl group bonded to a silicon atom, and a platinum-based catalyst, including the SiH vinyl group Various addition reaction inhibitors are added to the addition reaction curable organopolysiloxane composition (hereinafter simply referred to as “composition”) to obtain a cured product by addition reaction (hydrosilylation reaction), and the addition reaction at room temperature. It is well known that curing progress is suppressed by improving the long-term storage stability, and when used, the addition reaction is accelerated by heating.

  Conventionally, the curing rate of the addition crosslinking reaction is generally adjusted by the quantitative balance of the platinum catalyst and the addition reaction control agent, and the development of a curing accelerator effective for the addition reaction has been desired.

  Japanese Unexamined Patent Publication No. 2000-265067 (Patent Document 1) discloses a (meth) acrylic acid ester compound having a melting point of 40 ° C. or more as a curing accelerator, but a specific system using acetylene alcohol as a control system. However, there was a problem that the effect could not be fully exhibited.

JP 2000-265067 A

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the addition hardening type organopolysiloxane composition containing an addition reaction hardening accelerator, and its hardening acceleration method.

  As a result of intensive studies to achieve the above object, the present inventor is excellent in a compound having at least one carboxy group in one molecule as a curing accelerator for addition reaction, and by blending the compound, The inventors have found that the addition-curable organopolysiloxane composition can be rapidly cured by heating at the time of curing while maintaining the storage stability equivalent to that of the prior art to cure the addition-curable organopolysiloxane composition.

Accordingly, the present invention provides the following addition-curable organopolysiloxane composition and method for accelerating the curing thereof.
[1] (A) an organopolysiloxane containing an average of two or more silicon-bonded alkenyl groups in one molecule;
(B) Organohydrogenpolysiloxane containing at least two or more silicon-bonded hydrogen atoms in one molecule:
An amount such that the number of hydrogen atoms bonded to silicon atoms contained in one molecule of this component is 0.5 to 5.0 per alkenyl group of the organopolysiloxane of component (A),
(C) a catalytic amount of a catalyst for hydrosilylation reaction,
(D) a reaction control agent,
(E) An addition-curable organopolysiloxane composition containing a curing accelerator having at least one carboxy group in one molecule.
[2] Addition-curable organopolysiloxane composition, (E) a curing accelerator having at least one carboxy group in one molecule, and heat-curing the composition A method for accelerating curing of an organopolysiloxane composition.
[3] An addition-curable organopolysiloxane composition is
(A) an organopolysiloxane containing an average of two or more silicon-bonded alkenyl groups in one molecule;
(B) Organohydrogenpolysiloxane containing at least two or more silicon-bonded hydrogen atoms in one molecule:
An amount such that the number of hydrogen atoms bonded to silicon atoms contained in one molecule of this component is 0.5 to 5.0 per alkenyl group of the organopolysiloxane of component (A),
(C) a catalytic amount of a catalyst for hydrosilylation reaction,
(D) The curing acceleration method according to [2], which contains a reaction control agent.

  ADVANTAGE OF THE INVENTION According to this invention, hardening can be accelerated | stimulated at the time of hardening use, maintaining the long-term storage stability of an addition-curable organopolysiloxane composition.

In the present invention, (E) a curing accelerator having at least one carboxy group in one molecule is blended with an addition-curable organopolysiloxane composition, and the composition is heated and cured to thereby cure the composition. Curing can be promoted.
As the addition-curable organopolysiloxane composition,
(A) an organopolysiloxane containing an average of two or more silicon-bonded alkenyl groups in one molecule;
(B) an organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms in one molecule;
(C) a catalyst for hydrosilylation reaction,
(D) a reaction control agent,
The one containing is preferred.

[(A) component]
The organopolysiloxane of component (A) is a base polymer of the composition of the present invention, and has an average of at least two alkenyl groups bonded to silicon atoms in one molecule (usually 2 to 50, preferably 2 to 2). About 20).

  (A) As an alkenyl group in a component, Preferably it is C2-C12, More preferably, a C2-C6 alkenyl group is mentioned, for example. Specific examples thereof include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group, and a vinyl group is particularly preferable. Examples of the bonding position of the alkenyl group of component (A) include molecular chain terminals and / or molecular chain side chains.

  (A) As an organic group couple | bonded with silicon atoms other than the alkenyl group in a component, for example, the same or different unsubstituted or substituted, preferably 1 to 10 carbon atoms having no aliphatic unsaturated bond Valent hydrocarbon group. Specific examples thereof include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group and heptyl group; aryl groups such as phenyl group, tolyl group, xylyl group and naphthyl group; benzyl group, Aralkyl groups such as phenethyl group; halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group and the like, and methyl group and phenyl group are particularly preferable.

  The molecular structure of such component (A) includes, for example, linear diorganopolysiloxane in which the main chain is composed of repeating diorganosiloxane units and both ends of the molecular chain are blocked with triorganosiloxy groups. , Cyclic, branched, and three-dimensional network.

  The viscosity of component (A) at 25 ° C. is in the range of 100 to 500,000 mPa · s because the physical properties of the resulting silicone rubber are good and the handling workability of the composition is good. It is particularly preferable that it is in the range of 300 to 100,000 mPa · s. In the present invention, the viscosity can be measured with a rotational viscometer or the like (the same applies hereinafter).

Examples of the organopolysiloxane of the component (A) include, for example, a trimethylsiloxy group-capped dimethylsiloxane / methylvinylsiloxane copolymer, a molecular chain both-ends trimethylsiloxy group-capped methylvinylpolysiloxane, and both molecular chains. Terminal trimethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer, molecular chain both ends dimethylvinylsiloxy group-blocked dimethylpolysiloxane, molecular chain both ends dimethylvinylsiloxy group-blocked methylvinylpolysiloxane, molecular chain both ends Dimethylvinylsiloxy-blocked dimethylsiloxane / methylvinylsiloxane copolymer, dimethylvinylsiloxy-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer Both ends of the molecular chain divinyl trimethylsiloxy group-blocked dimethylpolysiloxane with both molecular chain terminals by trimethylsiloxy blocked with dimethylvinylsiloxy groups, wherein: the siloxane units of the formula R ¹ ₃ SiO _0.5: R ¹ ₂ R ² SiO _^0.5, A copolymer comprising a siloxane unit represented by the formula: R ¹ ₂ SiO and a siloxane unit represented by the formula: SiO ₂ ; a siloxane unit represented by the formula: R ¹ ₃ SiO _0.5 and a formula: R ¹ _{2 A} copolymer comprising a siloxane unit represented by R ² SiO _0.5 and a siloxane unit represented by the formula: SiO ₂ , a siloxane unit represented by the formula: R ¹ ₂ R ² SiO _0.5 and a formula: R ¹ ₂ SiO siloxane units of the formula are: copolymers comprising siloxane units represented by SiO _2, wherein: the siloxane units and a small amount of the formula represented by R ¹ R ² SiO: R ¹ siloxane units or formula represented by iO _1.5: R ² SiO _1.5 and copolymers comprising siloxane units represented by, and mixtures of two or more of these organopolysiloxanes.

Here, R ¹ in the above formula is the same or different unsubstituted or substituted, preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms and having no aliphatic unsaturated bond, for example, a methyl group Alkyl groups such as ethyl group, propyl group, butyl group, pentyl group, hexyl group and heptyl group; aryl groups such as phenyl group, tolyl group, xylyl group and naphthyl group; aralkyl groups such as benzyl group and phenethyl group; Examples thereof include halogenated alkyl groups such as a methyl group, 3-chloropropyl group, and 3,3,3-trifluoropropyl group. R ² in the above formula is preferably an alkenyl group having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, such as vinyl group, allyl group, butenyl group, pentenyl group, hexenyl. Group and heptenyl group.

[Component (B)]
The organohydrogenpolysiloxane of component (B) is a cross-linking agent for the composition of the present invention, and contains at least two hydrogen atoms (that is, SiH groups) bonded to silicon atoms in one molecule. (B) As a bond position of the hydrogen atom couple | bonded with the silicon atom of a component, a molecular chain terminal and / or molecular chain side chain are mentioned, for example.

  (B) As an organic group couple | bonded with the silicon atom of a component, for example, the same or different unsubstituted or substituted, preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, which does not have an aliphatic unsaturated bond. Can be mentioned. Specific examples thereof include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, cyclohexyl group and heptyl group; aryl groups such as phenyl group, tolyl group, xylyl group and naphthyl group; Aralkyl groups such as benzyl group and phenethyl group; halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group and 3,3,3-trifluoropropyl group are exemplified, and methyl group and phenyl group are particularly preferable.

Examples of the molecular structure of the component (B) include linear, cyclic, branched, and three-dimensional network.
The viscosity at 25 ° C. of component (B) is in the range of 0.1 to 1,000 mPa · s because the physical properties of the resulting silicone rubber are good and the handling workability of the composition is good. It is preferable that it is in the range of 5 to 500 mPa · s.
This organohydrogenpolysiloxane has at least 2, preferably 3 or more (usually 3 to 300), more preferably about 3 to 100 hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule. The number of silicon atoms in the molecule is 2 to 300, preferably about 3 to 150.

Examples of the organohydrogenpolysiloxane of component (B) include tris (dimethylhydrogensiloxy) methylsilane, tris (dimethylhydrogensiloxy) phenylsilane, 1,1,3,3-tetramethyldisiloxane, 1, 3,5,7-tetramethylcyclotetrasiloxane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane / dimethylsiloxane cyclic copolymer, trimethylsiloxy group-blocked methylhydrogenpolysiloxane with both molecular chains, trimethyl with both molecular chains Siloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane / methylphenylsiloxane copolymer at both ends of the molecular chain Molecular chain both ends dimethylhydrogensiloxy group-blocked dimethylpolysiloxane, Molecular chain both ends dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, Molecular chain both ends dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylphenyl Siloxane copolymers, dimethylhydrogensiloxy group-blocked methylphenylpolysiloxanes with molecular chain ends, and some or all of the methyl groups of these compounds are aryl groups such as ethyl groups and propyl groups, and aryl groups such as phenyl groups A copolymer substituted by a group, and further comprising a siloxane unit represented by the formula: R ¹ ₃ SiO _0.5 , a siloxane unit represented by the formula: R ¹ ₂ HSiO _0.5 and a siloxane unit represented by the formula: SiO ₂ , Represented by the formula: R ¹ ₂ HSiO _0.5 Siloxane units of the formula: consisting of siloxane units represented by SiO ₂ copolymer, wherein: the siloxane units represented by the formula R ¹ HSiO: siloxane unit or the formula represented by R ¹ SiO _1.5: siloxane represented by HSiO _1.5 Examples thereof include a copolymer composed of units and a mixture composed of two or more of these organopolysiloxanes. R ¹ in the above formula is the same as described above.

  The blending amount of component (B) is the alkenyl group in the whole composition (in the case where only the component (A) has an alkenyl group in the whole composition, the alkenyl group bonded to the silicon atom in the component (A)). The amount of hydrogen atoms bonded to the silicon atom in the component (B) is 0.5 to 5.0 mol, preferably 0.8 to 3.0 mol, per 1 mol. If the amount of hydrogen atoms is less than 0.5 mol, the composition may not be cured sufficiently. On the other hand, if the amount of hydrogen atoms exceeds 5 mol, the resulting cured product may be extremely inferior in heat resistance.

[Component (C)]
As long as the hydrosilylation reaction catalyst of component (C) has an action of promoting an addition reaction (hydrosilylation reaction) between the alkenyl group-containing organopolysiloxane of component (A) and the organohydrogenpolysiloxane of component (B), There is no particular limitation. As the component (C), for example, a conventionally known hydrosilylation reaction catalyst can be used. Specific examples thereof include chloroplatinic acid, alcohol-modified chloroplatinic acid, coordination compounds of chloroplatinic acid and olefins, vinylsiloxane or acetylene compounds, tetrakis (triphenylphosphine) palladium, chlorotris (triphenylphosphine) rhodium, etc. Of these, platinum compounds are particularly preferred.

  The amount of component (C) added may be an effective amount as a hydrosilylation reaction catalyst, but can be appropriately increased or decreased depending on the desired curing rate. Usually, 0.1 to 1,000 ppm, preferably 1 to 500 ppm, more preferably 10 to 100 ppm in terms of the mass of the catalyst metal element based on the total amount of the component (A) and the component (B). Is the amount. In addition, it is economically unpreferable if there is too much this compounding quantity.

[(D) component]
The component (D) is a compound having a curing inhibitory effect on the addition reaction catalyst, and all conventionally known control agent compounds can be used. Such compounds include phosphorus-containing compounds such as triphenylphosphine, nitrogen-containing compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole, sulfur-containing compounds, acetylenic compounds, compounds containing two or more alkenyl groups, hydroper Examples include oxy compounds.

  Since the degree of the curing delay effect by the control agent compound varies greatly depending on the chemical structure of the control agent compound, it is preferable to adjust the addition amount of the control agent compound to an optimum amount for each of the control agent compounds to be used. (A) It is 0.0001-1 mass part with respect to 100 mass parts of component, and can be 0.1-0.5 mass part especially. If the amount added is too small, long-term storage stability at room temperature may not be obtained. Conversely, if it is too large, curing may be hindered.

[(E) component]
Component (E) is a feature of the present invention and is a compound having at least one carboxy group in one molecule, and functions as a curing accelerator in an addition curing system.

  Examples of the compound having at least one carboxy group in one molecule include acetic acid, methoxyacetic acid, ethoxyacetic acid, propionic acid, butanoic acid, octanoic acid, lauric acid, palmitic acid, benzoic acid, salicylic acid, phthalic acid, Examples of malonic acid, trimellitic acid, and pyromellitic acid include saturated or unsaturated aliphatic carboxylic acids and aromatic carboxylic acids that usually contain about 1 to 4 carboxyl groups in one molecule. It is sufficient to include at least one carboxy group in one molecule, and it may be a compound containing another functional group such as an unsaturated group, an ester group, an epoxy group, or an acrylic group. Moreover, what performed siloxane modification | denaturation may be used. However, compounds that do not contain nitrogen, sulfur, and phosphorus, which are known as addition curing inhibiting elements, are preferable, and the α-position carbon atom to which the carboxyl group is bonded does not have an aliphatic unsaturated bond. It is preferable. Maleic acid does not show any curing accelerating properties and exhibits a controlling effect.

  The amount used varies depending on the characteristics of the individual compounds and cannot be defined generally, but is preferably 100 times mol or less, more preferably 50 times mol or less with respect to the platinum atom. If it is used in excess of 100 times mole, there is a risk of dehydrogenation reaction with SiH groups. In addition, as a minimum of usage-amount, it is preferable to set it as 5 times mole or more with respect to a platinum atom, especially 10 times mole or more. If the amount used is too small, the curing acceleration effect may be inferior.

[Other ingredients]
In the present invention, in addition to the above components, other optional components can be blended within a range not impairing the object of the present invention. Examples of other optional components include crystalline silica, hollow filler, silsesquioxane, fumed titanium dioxide, magnesium oxide, zinc oxide, iron oxide, aluminum hydroxide, magnesium carbonate, calcium carbonate, zinc carbonate, and layered mica. , Carbon black, diatomaceous earth, glass fiber and other inorganic fillers, and fillers obtained by surface-treating these fillers with organosilicon compounds such as organoalkoxysilane compounds, organochlorosilane compounds, organosilazane compounds, and low molecular weight siloxane compounds Etc. Moreover, silicone rubber powder, silicone resin powder, etc. are mentioned.

  Furthermore, a creep hardening inhibitor, a plasticizer, a heat-resistant additive, a thixotropic agent, a pigment, a dye, an antifungal agent and the like can be added to the composition as long as the object of the present invention is not impaired. .

The addition-curable organopolysiloxane composition of the present invention can be prepared by mixing the above components according to a conventional method.
The resulting addition-curable organopolysiloxane composition can be cured by heating at 40 to 150 ° C., particularly 60 to 100 ° C. for 1 minute to 1 hour, particularly 5 minutes to 0.5 hour.

  In the present invention, the time (T10) from the start of curing to 10% of the maximum torque value measured by heating the composition at 90 ° C. using a rheometer is 1 to 6 minutes, particularly 2 It is preferably ~ 5 minutes.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In addition, in the following example, a viscosity shows the value in 25 degreeC measured with the rotational viscometer.

[Example 1]
Both ends of the molecular chain are blocked with vinyldimethylsilyl groups, 100 parts by mass of dimethylpolysiloxane having a viscosity at 25 ° C. of about 5,000 mPa · s, and a silicon atom-bonded hydrogen atom on the side chain of the molecular chain having a viscosity of 20 mPa · s. Dimethylsiloxane / methylhydrogensiloxane copolymer (silicon-bonded hydrogen atom content = 0.725 mass%) 1.24 parts by mass, 1-ethynylcyclohexanol 0.05 parts by mass, chloroplatinic acid / 1,3 -Mixing 0.15 parts by mass of dimethylpolysiloxane solution containing 1% by mass of divinyltetramethyldisiloxane complex as platinum atom content and 0.055 parts by mass of octanoic acid (carboxyl group / platinum atom = 50/1 molar ratio) Thus, composition A was prepared.

《Curing test》
The composition A was heated at 90 ° C. using a rheometer, and the time from the start of heating to the end of curing and T10 were measured. The results are shown in Table 1. T10 means the time from the start of curing until the torque value on the curing curve of the rheometer reaches 10% of the maximum torque value indicating the time when curing is completely completed.

[Example 2]
Composition B was prepared according to Example 1 except that 0.036 parts by mass of methoxyacetic acid (carboxyl group / platinum atom = 50/1 molar ratio) was used instead of 0.055 parts by mass of octanoic acid. The results of the curing test are shown in Table 1.

０．０３質量部（カルボキシル基／白金原子＝１２．５／１モル比）を使用した以外は実施例１に従い、組成物Ｃを調製した。硬化試験結果を表１に示した。 [Example 3]
Instead of 0.055 parts by mass of octanoic acid, the following compound 1

Composition C was prepared according to Example 1 except that 0.03 parts by mass (carboxyl group / platinum atom = 12.5 / 1 molar ratio) was used. The results of the curing test are shown in Table 1.

[Example 4]
Composition D was prepared according to Example 2 except that 0.3 parts by mass of tetravinyltetramethylcyclotetrasiloxane was used instead of 0.05 parts by mass of 1-ethynylcyclohexanol. The results of the curing test are shown in Table 1.

[Example 5]
Composition E was prepared according to Example 3 except that 0.3 parts by mass of tetravinyltetramethylcyclotetrasiloxane was used instead of 0.05 parts by mass of 1-ethynylcyclohexanol. The results of the curing test are shown in Table 1.

[Comparative Example 1]
Composition F was prepared according to Example 1 except that 0.055 parts by weight of octanoic acid was not used. The results of the curing test are shown in Table 1.

[Comparative Example 2]
Composition G was prepared according to Example 4 except that 0.036 parts by weight of methoxyacetic acid was not used. The results of the curing test are shown in Table 1.

Claims (3)

(A) an organopolysiloxane containing an average of two or more silicon-bonded alkenyl groups in one molecule;
(B) Organohydrogenpolysiloxane containing at least two or more silicon-bonded hydrogen atoms in one molecule:
An amount such that the number of hydrogen atoms bonded to silicon atoms contained in one molecule of this component is 0.5 to 5.0 per alkenyl group of the organopolysiloxane of component (A),
(C) a catalytic amount of a catalyst for hydrosilylation reaction,
(D) a reaction control agent,
(E) An addition-curable organopolysiloxane composition containing a curing accelerator having at least one carboxy group in one molecule.   An addition-curable organopolysiloxane comprising (E) a curing accelerator having at least one carboxy group in one molecule, and heat-curing the composition. A method for accelerating curing of the composition. Addition-curable organopolysiloxane composition is
(A) an organopolysiloxane containing an average of two or more silicon-bonded alkenyl groups in one molecule;
(B) Organohydrogenpolysiloxane containing at least two or more silicon-bonded hydrogen atoms in one molecule:
An amount such that the number of hydrogen atoms bonded to silicon atoms contained in one molecule of this component is 0.5 to 5.0 per alkenyl group of the organopolysiloxane of component (A),
(C) a catalytic amount of a catalyst for hydrosilylation reaction,
(D) The curing accelerating method according to claim 2, comprising a reaction control agent.