Silicone ladder polymer and process for producing the same
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsShigeyuki Yamamoto, Hiroyuki Nishimura, Hiroshi Adachi
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Abstract
A high-purity silicone ladder polymer of high molecular weight which contains 1 ppm or less of sodium, potassium, iron, copper, lead, magnesium, manganese and chlorine, and 1 ppb or less of uranium and thorium; and whose polymerization degree is 600 to 10000. Trialkoxysilane compounds or trichlorosilane compounds are hydrolyzed to produce a high-purity silicone ladder prepolymer whose polymerization degree is 5 to 600. The silicone ladder prepolymer is subjected to dehydrative condensation by using a nucleophilic reagent as a catalyst, and then purified in a dissolution/reprecipitation method to yield the silicone ladder polymer.
Claims5
A process for producing a high purity silicone ladder polymer containing 1 ppm or less of sodium, potassium, iron, copper, lead, magnesium, manganese and chlorine, and 1 ppb or less of uranium and thorium;
- the polymer being represented by a formula (1), ##STR4## wherein R.sub.1 represents a lower alkyl group an alkenyl group which is optionally substituted with an aryl group or an aryl group;
- R.sub.2, R.sub.3, R.sub.4 and R.sub.5 represent a hydrogen atom or a lower alkyl group;
- and n.sub.1 represents a natural number of 600 to 10000, comprising the steps of:
- adding a nucleophilic reagent to an organic solvent solution of a silicone ladder prepolymer comprising 1 ppm or less of sodium, potassium, iron, copper, lead, magnesium, manganese and chlorine, and 1 ppb or less of uranium and thorium;
- the prepolymer being represented by a formula (2), ##STR5## wherein R.sub.1 represents a lower alkyl group, an alkenyl group which is optionally substituted with an aryl group or an aryl group;
- R.sub.2, R.sub.3, R.sub.4 and R.sub.5 represent a hydrogen atom or a lower alkyl group;
- and n.sub.2 represents a natural number of 5 to 600 to initiate dehydrative condensation to yield a product of high molecular weight;
- and
- purifying the product by a dissolution/reprecipitation method.
A process for producing a high purity silicone ladder prepolymer containing 1 ppm or less of sodium, potassium, iron, copper, lead, magnesium, manganese and chlorine, and 1 ppb or less of uranium and thorium;
- the prepolymer being represented by a formula (2), ##STR7## wherein R.sub.1 represents a lower alkyl group, an alkenyl group which is optionally substituted with an aryl group or an aryl group;
- R.sub.2, R.sub.3, R.sub.4 and R.sub.5 represent a hydrogen atom or a lower alkyl group;
- and n.sub.2 represents a natural number of 5 to 600, comprising the steps of:
- dissolving a trialkoxysilane compound of formula (3),
- HSiOR.sub.6 OR.sub.7 OR.sub.8
- wherein R.sub.6, R.sub.7 and R.sub.8 represent a lower alkyl group;
- or the trialkoxysilane compound of the formula (3) and a trialkoxysilane compound of formula (4),
- R.sub.9 SiOR.sub.6 OR.sub.7 OR.sub.8
- wherein R.sub.9 represents a lower alkyl group, an alkenyl group which is optionally substituted with an aryl group or an aryl group, and R.sub.6, R.sub.7 and R.sub.8 represent a lower alkyl group in an organic solvent to produce a solution containing said prepolymer in a concentration of 0.01 to 0.3 g/ml;
- hydrolyzing the solution at a temperature of -30.degree. C. to 30.degree. C. with pure water from which substantially all impurities have been removed to which hydrogen chloride has been added under cooling to produce a hydrolyzate;
- and
- washing the hydrolyzate with pure water from which substantially all impurities have been removed.
A process for producing a high purity silicone ladder prepolymer containing 1 ppm or less of sodium, potassium, iron, copper, lead, magnesium, manganese and chlorine, and 1 ppb or less of uranium and thorium;
- the prepolymer being represented by a formula (2), ##STR8## wherein R.sub.1 represents a lower alkyl group, an alkenyl group which is optionally substituted with an aryl group or an aryl group;
- R.sub.2, R.sub.3, R.sub.4 and R.sub.5 represent a hydrogen atom or a lower alkyl group;
- and n.sub.2 represents a natural number of 5 to 600, comprising the steps of:
- dissolving a trichlorosilane compound of a formula (5), HSiCl.sub.3 ;
- or the trichlorosilane compound of the formula (5) and a trichlorosilane compound of a formula (6),
- R.sub.9 SiCl.sub.3
- wherein R.sub.9 represents a lower alkyl group, an alkenyl group which is optionally substituted with an aryl group or an aryl group in an organic solvent to produce a solution containing said prepolymer in a concentration of 0.01 to 0.3 g/ml;
- hydrolyzing the solution at a temperature of -30.degree. C. to 30.degree. C. with pure water from which substantially all impurities have been removed to which hydrogen chloride optionally has been added under cooling to produce a hydrolyzate;
- and
- washing the hydrolyzate with pure water from which substantially all impurities have been removed.
Dependencies are inferred from the claim text.