JP3292065B2 - Silicone-modified polyurethane elastomer and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a transparent thermoplastic silicone-modified polyurethane elastomer and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Generally, a silicone elastomer is a thermosetting elastomer obtained by crosslinking a linear silicone rubber compound or a liquid silicone rubber with a vulcanizing agent or a catalyst.
Although it has excellent heat resistance, cold resistance, water resistance, chemical resistance, electrical properties, gas permeability, etc., it has poor tensile strength and tear strength. For this reason, in order to improve tensile strength and tear strength, conventionally, silicone elastomers are highly filled with silica powder as a reinforcing agent, so that it is difficult to obtain a transparent elastomer, and dispersion and strength of the filler are also difficult. Problems remain in terms.

On the other hand, thermoplastic elastomers can be recycled from the viewpoint of ecology and are considered to be useful. Urethane elastomers are one of the thermoplastic elastomers having high strength. Recently, with the aim of improving the surface lubricity of this thermoplastic urethane elastomer,
It is known to blend silicone oils and copolymerize with reactive silicone oils. However, in the case of blending with silicone oil, problems such as lack of lubricity after bleed-out of silicone oil and trouble of electrical contact of the bleed-out silicone oil are cited.In copolymerization with reactive silicone oil, ethylene glycol is used. Due to the poor solubility of silicone oil with a chain extender such as propylene glycol, butylene glycol, and the like, there is a drawback that when a silicone oil is blended in a high amount, it is difficult to obtain a transparent elastomer.

[0004] The present invention has been made in view of the above circumstances,
A high-strength thermoplastic silicone-modified polyurethane elastomer which is transparent and has high heat resistance, cold resistance, weather resistance, and chemical resistance of a conventional thermosetting silicone elastomer, and a method for producing the same.

[0005]

Means for Solving the Problems and Embodiments of the Invention The present inventors have made intensive studies to achieve the above object, and as a result, have found that siloxanes 30 to 9 represented by the following general formula (1) can be obtained.
By reacting 4% by weight, 1 to 20% by weight of a branched diol or diamine represented by the following general formula (2), and 5 to 69% by weight of an organic diisocyanate compound as essential components, 30% by weight or more of R with finding ^{that 1} ₂ thermoplastic silicone-modified polyurethane elastomer having an organopolysiloxane chain in the molecular chain is a SiO units is obtained, this elastomer with a transparent thermoplastic elastomers, yet possessed conventional thermosetting silicone elastomer Has heat resistance, cold resistance, water resistance, weather resistance,
The inventors have further found that the strength is high, and have accomplished the present invention.

[0006]

Embedded image (Wherein, R ¹ is the same or different alkyl group or aryl group having 1 to 8 carbon atoms, R ² is an organic group having a hydroxyl group, n is an integer of 15 to ²⁰⁰ , and R ³ is carbon atom. (The same or different alkyl groups or aryl groups of the formulas 1 to 7, and X is a hydroxyl group or an amino group.)

Accordingly, the present invention provides (1) a thermoplastic polyurethane elastomer having an organopolysiloxane chain in a molecular chain, wherein 30 to 94% by weight of a siloxane represented by the above-mentioned general formula (1) is used; A polyurethane elastomer obtained by reacting 1 to 20% by weight of a branched diol or diamine represented by (2) and 5 to 69% by weight of an organic diisocyanate compound as essential components, and 30% by weight of the reaction product silicone-modified polyurethane elastomers% or more characterized in that it is a R ¹ ₂ SiO units, min represented by (2) a siloxane 30 to 94 wt% of the above formula (1), the general formula (2) 1-20% by weight of a branched diol or a diamine and 5-69% by weight of an organic diisocyanate compound are reacted as essential components. R ¹ ₂ SiO units, wherein Rukoto is to provide a method of manufacturing a silicone-modified polyurethane elastomer is 30 wt% or more.

Hereinafter, the present invention will be described in more detail.
The silicone-modified polyurethane elastomer of the present invention,
A thermoplastic polyurethane elastomer having an organopolysiloxane chain in a molecular chain, which is a reaction product of the following reactive siloxane, a short-chain diol or diamine (chain extender), and an organic diisocyanate compound.

In the polyurethane elastomer of the present invention, the reactive siloxane is a siloxane containing hydroxyl groups at both ends represented by the following general formula (1).

[0010]

Embedded image

In the formula, R ¹ is the same or different alkyl group or aryl group having 1 to 8 carbon atoms, and particularly preferably a methyl group and a phenyl group in view of being widely used industrially.

N is an integer of 15 to 200, and n is 15
If it is smaller, a transparent elastomer can be obtained even when an unbranched diol or diamine is used as a chain extender, but the cold resistance, heat resistance and water resistance of the silicone elastomer due to the short siloxane chain length And characteristics such as weather resistance are difficult to obtain. Conversely, if n is too large, the rubber strength will be weak.

R ² may be any organic group having a hydroxyl group at the terminal, and the following groups having an alkylene group, polyether group or polyester group are preferred.

[0014]

Embedded image Among these, _{- (CH 2) 3 OH,} - (CH 2) 4
O (CH ₂ ) ₂ OH is preferred.

The use amount of the siloxane of the above formula (1) is 30
~ 94% by weight. If less than 30% by weight, cold resistance,
Characteristics such as heat resistance, water resistance, and weather resistance cannot be obtained. Conversely, if it is more than 94% by weight, the rubber strength becomes weak. Preferably it is 40 to 70% by weight.

Next, the short-chain diol or diamine serving as a chain extender is a branched diol or diamine represented by the following general formula (2).

[0017]

Embedded image (In the formula, R ³ is the same or different alkyl group or aryl group having 1 to 7 carbon atoms, and X is a hydroxyl group or an amino group.)

Examples of R ³ include a methyl group, an ethyl group, a propyl group, a phenyl group and a 4-methylphenyl group.

The number of carbon atoms in the main chain between the hydroxyl group and the amino group represented by X is 3, and when it is smaller than 3, X hardly reacts with the isocyanate group, the addition polymerization reaction takes time, and Elastomer cannot be obtained. Conversely, if it is greater than 3, the elastomer will be a low-strength elastomer or an elastomer having a surface tackiness.

When R ³ is hydrogen, the compatibility in the present invention becomes poor, and a highly transparent elastomer cannot be obtained.

As the diol and diamine of the formula (2),
Preferably 2,2-dimethyl-1,3-diol, 2,
2-diethyl-1,3-diol, 2,2-dimethyl-
1,3-diamine and the like.

The amount of the diol or diamine of the formula (2) used as a chain extender is 1 to 20% by weight,
When the amount is less than 1% by weight, an elastomer cannot be obtained, and a liquid material is obtained. On the contrary, when the amount is more than 20% by weight, a resinous material having poor elasticity is obtained. More preferably, 5
-10% by weight.

Examples of the organic diisocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and 2,4'- Diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-
Biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 3,3 '
-Dichloro-4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3 -Cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl −4
4'-dicyclohexylmethane diisocyanate and the like.

The amount of the diisocyanate is 5 to 69% by weight based on the polyurethane elastomer of the present invention.
If the amount is less than 5% by weight, an elastomer cannot be obtained, and the material becomes a liquid. On the other hand, if the amount is more than 69% by weight, a very hard and brittle resinous material having poor elasticity is obtained. More preferably, it is 20 to 50% by weight.

Incidentally, to the extent that the characteristics of the present invention are not impaired,
A generally used long-chain polyether diol, polyester diol, or the like having an average molecular weight of 500 to 4,000 may be blended.

[0026] In the polyurethane elastomer of the present invention, the 30 wt% or more, particularly 30 to 94 wt% R ¹ ₂
It is a SiO unit. If the amount is less than 30% by weight, the heat resistance, cold resistance, water resistance and weather resistance of the silicone are hardly obtained. Preferably it is 40 to 70% by weight.

The polyurethane elastomer of the present invention can be synthesized by reacting a hydroxyl-containing siloxane of the above formula (1) with a branched diol or diamine of the formula (2) or diisocyanate. As a synthesis method, a generally known method for synthesizing a thermoplastic urethane elastomer may be used. For example, a siloxane containing both terminal hydroxyl groups and a branched diol or a branched diamine (chain extender) are kept at 60 to 90 ° C. A method of dropping diisocyanate with stirring, a method of reacting the siloxane, the chain extender and the diisocyanate in an aprotic solvent, or a method of raising the temperature of the siloxane and the chain in a twin-screw extruder without solvent under a temperature increase A method of reacting a long extender and a diisocyanate, and furthermore, a siloxane and a diisocyanate After reacting, stepwise reaction method for chain extension with a diol or a diamine may also be mentioned.

In synthesizing the polyurethane elastomer of the present invention, a catalyst and a stabilizer can be used if necessary. These catalysts and stabilizers can be added at any stage.

As the catalyst, for example, triethylamine,
Examples include nitrogen-containing compounds such as triethylenediamine, metal salts such as potassium acetate, zinc stearate and tin octylate, and organic metal compounds such as dibutyltin dilaurate.

As the stabilizer, a stabilizer against ultraviolet rays such as substituted benzotriazoles and a stabilizer against thermal oxidation such as phenol derivatives can be added.

The polyurethane elastomer of the present invention is cut into pellets by, for example, a twin-screw extruder, and then various molding machines generally used, ie, an extrusion molding machine, an injection molding machine, a blow molding machine, a calender molding machine, and a press. Films of various plastics such as polyester, nylon, polyvinyl chloride, ABS, OPP, CPP, etc. in liquid state, used as molding elastomer by molding machine or dissolved in organic solvent or produced in aprotic organic solvent As a primer coating agent for sheets and sheets, as a top coating agent, as a surface coating agent for various metal plates such as iron plates, steel plates, and aluminum plates; as a top coating agent for various functional papers such as thermal paper; Used as a paint or surface coating for paper, natural leather, artificial leather, synthetic leather, wood, etc. It can be.

Further, since the polyurethane elastomer of the present invention is transparent, it can be used as a protective coating or potting agent for a color indicator, or as a television, video,
As an overcoating agent for remote control of audio equipment, switch parts of telephones, etc., unlike silicone rubber, it is a thermoplastic that is easy to mold and retains rubber properties at low and high temperatures, so it can be used for wire coverings for transport equipment, copy machines, Applications include rubber rolls such as printers, oxygen-enriched membranes, artificial organs such as artificial blood vessels and artificial hearts, and medical instruments such as catheters.

[0033]

The polyurethane elastomer of the present invention comprises:
A siloxane compound containing hydroxyl groups at both ends is used as a long-chain diol compound, and a branched diol or a branched diamine that is easily compatible with the siloxane is used as a chain extender,
This polyurethane elastomer is a transparent thermoplastic elastomer that has the heat resistance, cold resistance, water resistance, weather resistance, and chemical resistance of conventional thermosetting silicone elastomers, and has high strength and is recycled after molding. It is also possible.

[0034]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example 1 155 parts by weight of 4,4'-diphenylmethane diisocyanate was placed in a metal kneader having a content of 1 L, and a siloxane having a hydroxyl group at both ends represented by the following general formula (1-1) having a degree of polymerization of n = 20. Siloxane 36
After 0 parts by weight were added and dissolved at 70 to 90 ° C., stirring was performed for 2 hours. Thereafter, 42.1 parts by weight of neopentyl glycol was added, kneaded for 30 minutes, and defoamed. The obtained elastomer was pressed at 220 ° C. to make a 1 mm thick sheet and physical properties were measured. It should be noted that the disappearance of the isocyanate group depends on I
It was confirmed by the R spectrum.

[0036]

Embedded image

Example 2 Instead of the siloxane of Example 1, 682 parts by weight of a siloxane having a polymerization degree n = 40 in the formula (1-1), and 2,2-diethyl-1,3 instead of neopentyl glycol -A transparent elastomer was obtained in the same manner as in Example 1 except that 75 parts by weight of propanediol was used.

Example 3 The isocyanate of Example 1 was replaced with 163 parts by weight of hydrogenated MDI, and siloxane and neopentyl glycol were heated and stirred at 80 ° C., and hydrogenated MDI was added dropwise and kneaded. After defoaming, a transparent elastomer was obtained in the same manner as in Example 1.

Example 4 The isocyanate of Example 1 was replaced with 108 parts by weight of tolylene diisocyanate, and the siloxane was 497 parts by weight of a siloxane represented by the following general formula (1-2), wherein n = 9 and m = 5. A transparent silicone elastomer was obtained in the same manner as in Example 1 except that the above procedure was repeated.

[0040]

Embedded image

Example 5 In a 1 L flask, 31 parts by weight of 4,4'-diphenylmethane diisocyanate and 150 parts by weight of dimethylformamide as a solvent were stirred and stirred at 70 ° C., and used there in Example 1. 72 parts by weight of siloxane, neopentyl glycol 8.41
A uniform solution of 400 parts by weight of toluene and 400 parts by weight of dried toluene was added dropwise and stirred at 70 to 80 ° C. for 6 hours to obtain a transparent silicone-modified urethane elastomer solution.

This solution was applied to a glass plate, left to stand overnight, and dried in a heater at 80 ° C. for 3 hours to obtain a transparent rubber film.

Comparative Example 1 Dimethylsiloxane Unit 9
100 parts by weight of methylvinylpolysiloxane having an average degree of polymerization of about 8,000 consisting of 9.5 mol% and 0.5 mol% of methylvinylsiloxane units, and treated silica R-972
50 parts by weight (manufactured by Nippon Aerosil Co., Ltd.) were kneaded with two rolls. Then, the organic peroxide 2,5-dimethyl-2,
0.5 part by weight of 5-di (t-butylperoxy) hexane was kneaded, and the obtained compound was cured at 165 ° C. for 10 minutes to obtain a 1 mm thick rubber sheet.

Comparative Example 2 320 parts by weight of a siloxane having a degree of polymerization of n = 10 in the formula (1-1) in place of the siloxane of Example 1 and 24 parts of 1,4-butylene glycol in place of neopentyl glycol. A transparent elastomer was obtained in the same manner as in Example 1 except that 9 parts by weight was used.

Comparative Example 3 In place of neopentyl glycol of Example 1, 1,4-butylene glycol was used.
An elastomer was obtained in the same manner as in Example 1 except that 4 parts by weight was used. The 1 mm thick sheet was white.

Comparative Example 4 A transparent elastomer was obtained in the same manner as in Example 1 except that 320 parts by weight of siloxane having a polymerization degree n = 10 in the formula (1-1) was used instead of the siloxane of Example 1. Was.

[Comparative Example 5] In a 1 L flask, 31 parts by weight of 4,4'-diphenylmethane diisocyanate and 150 parts by weight of dimethylformamide as a solvent were charged, stirred at 70 ° C, and used there in Example 1. 45.3 parts by weight of the obtained siloxane, 16.0 parts by weight of polytetramethylene glycol diol (average molecular weight: 1,000),
7.28 parts by weight of 1,4-butylene glycol and toluene / dimethylformamide as a solvent (weight ratio: 1 /
A homogeneous solution of 350 parts by weight of the mixed solvent of 1) was added dropwise,
By stirring at -80 ° C for 6 hours, a solution of a transparent silicone-modified urethane elastomer was obtained.

However, when this solution was dried in the same manner as in Example 5 to form a rubber film, it became cloudy.

The elastomer properties of Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1, and the relationship between temperature and viscoelasticity in Examples 1 and 2 is shown in FIGS.
The relationship between temperature and viscoelasticity was measured at a vibration frequency of 30.0 Hz.

[0050]

[Table 1]

From the results shown in Table 1, the elastomer of the present invention is a transparent elastomer, and Comparative Example 1 reinforced with silica was used.
It can be seen that they are superior in strength as compared with Comparative Examples 2 and 3, which were white elastomers.

Further, from FIGS. 1 and 2, it can be seen that the hardness of the elastomer of the present invention is small in a wide temperature range.

That is, it was confirmed that the elastomer of the present invention is a transparent thermoplastic elastomer, and has high heat resistance and cold resistance as high as that of the thermosetting silicone elastomer, and also has high strength.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between temperature and viscoelasticity in the elastomer of Example 1.

FIG. 2 is a graph showing the relationship between temperature and viscoelasticity in the elastomer of Comparative Example 2.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-76275 (JP, A) JP-A-57-117524 (JP, A) JP-A-4-180914 (JP, A) (58) Field (Int. Cl. ⁷ , DB name) C08G 18/00-18/87

Claims (2)

(57) [Claims] 1. A thermoplastic polyurethane elastomer having an organopolysiloxane chain in a molecular chain, wherein the thermoplastic polyurethane elastomer has the following general formula (1): (Wherein, R ¹ is the same or different alkyl group or aryl group having 1 to 8 carbon atoms, R ² is an organic group having a hydroxyl group, and n is an integer of 15 to ²⁰⁰ ). 30 to 94% by weight of siloxane and the following general formula (2) (Wherein, R ³ is the same or different alkyl group or aryl group having 1 to 7 carbon atoms, and X is a hydroxyl group or an amino group).
% By weight and the organic diisocyanate compound 5 to 69
A polyurethane elastomer obtained by reacting a weight percent as essential components, a silicone-modified polyurethane elastomer least 30 wt% of said reaction product characterized in that it is a R ¹ ₂ SiO units. 2. The following general formula (1): (Wherein, R ¹ is the same or different alkyl group or aryl group having 1 to 8 carbon atoms, R ² is an organic group having a hydroxyl group, and n is an integer of 15 to ²⁰⁰ ). 30 to 94% by weight of siloxane and the following general formula (2) (Wherein, R ³ is the same or different alkyl group or aryl group having 1 to 7 carbon atoms, and X is a hydroxyl group or an amino group).
% By weight and the organic diisocyanate compound 5 to 69
The method of producing the silicone-modified polyurethane elastomer R ¹ ₂ SiO unit is 30 wt% or more, characterized in that the reaction of wt% as essential components.