摘要:
An organopolysiloxane gum is continuously prepared by (I) mixing at least one cyclopolysiloxane with an end capping agent, (II) feeding the mixture to a self-cleaning reactor along with a polymerization catalyst of thermal decomposition type, and effecting polymerization at a temperature of 80-130° C., (III) heating the reaction mixture of step (II) at a temperature of 130-200° C. under subatmospheric pressure for deactivating the catalyst, thereby terminating the polymerization reaction, and (IV) continuously removing the cyclopolysiloxane and volatile components from the reaction product.
摘要:
An organopolysiloxane gum is prepared by polymerizing a cyclic organopolysiloxane with a low molecular weight linear organopolysiloxane end-blocked with a triorganosilyl group in the presence of a thermally decomposable catalyst. After the polymerization reaction, the catalyst is deactivated by heating the reaction product under a subatmospheric pressure of typically up to 500 mmHg.
摘要:
In a first step, basic components including (A) 100 parts by weight of an organopolysiloxane gum, (B) 5-100 parts by weight of a reinforcing silica filler, and (C) 0.1-30 parts by weight of a processing aid are fed batchwise to a closed mixer for mixing them until uniform. In a second step, the mixture is continuously fed into a kneader/extruder for heat treating. The first step achieves quick dispersion and cooperates with the second step for the efficient production of a heat-curable silicone rubber compound.
摘要:
In a first step, basic components including (A) 100 parts by weight of an organopolysiloxane gum, (B) 5-100 parts by weight of a reinforcing silica filler, and (C) 0.1-30 parts by weight of a processing aid are fed batchwise to a closed mixer for mixing them at a temperature of room temperature to 150.degree. C. In a second step, the mixture is fed into a kneader/mixer for heat treating at a temperature of 150-250.degree. C. The first step achieves quick dispersion and cooperates with the second step to form a heat-curable silicone rubber compound in an efficient manner.
摘要:
A silicone rubber composition comprising an organopolysiloxane containing at least two alkenyl radicals and having a degree of polymerization of at least 100, an organopolysiloxane or organosilane, reinforcing silica, and an alkali metal salt of phosphoric acid has minimized plasticity recovery with time and improved storage stability and cures with an organic peroxide or addition reaction curing agent into a silicone rubber having improved compression set and yellowing resistance.
摘要:
A method for producing a silicone rubber compound in a reduced blending time, and which imparts excellent resistance to plasticity reversion and the cured silicone rubber prepared without heat treatment has excellent resistance to compression set. (A) an organopolysiloxane with polymerization degree of at least 100 represented by the following average compositional formula (I): R1aSiO(4-a)/2 (I) (R1: a substituted or unsubstituted monovalent hydrocarbon group, a: 1.95 to 2.05), (B) a reinforcing silica having a specific surface area (BET) of at least 50 m2/g, and (C) a preliminary hydrolysis product of (C-1) an alkoxysilane represented by the following formula (II): R2mSi(OR3)4-m (II) (R2: hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, R3: a substituted or unsubstituted alkyl group, m: 0, 1, 2, or 3), and (C-2) water at a molar amount 0.3 to 5 times the alkoxy group in the alkoxysilane of component (C-1) are mixed and heated.
摘要:
A method for producing a silicone rubber compound in a reduced blending time and which imparts excellent resistance to plasticity reversion, and the cured silicone rubber prepared without heat treatment has excellent resistance to compression set. The method comprises mixing components: (A) an organopolysiloxane having a polymerization degree of at least 100 represented by the following average compositional formula (I): R1aSiO(4−a)/2 (I) wherein R1 is independently a substituted or unsubstituted monovalent hydrocarbon group, and a is 1.95 to 2.05; (B) a reinforcing silica having a specific surface area as measured by BET absorption method of at least 50 m2/g, (C) an alkoxysilane represented by the following formula (II): R2mSi(OR3)4−m (II) wherein R2 is independently hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, R3 is independently a substituted or unsubstituted alkyl group, and m is 0, 1, 2, or 3, and (D) water, and the heat treatment.
摘要:
An organopolysiloxane gum is continuously prepared by (I) mixing at least one cyclopolysiloxane with an end capping agent, (II) feeding the mixture to a self-cleaning reactor along with an alkaline polymerization catalyst, and effecting polymerization at a temperature of 100 to 250° C. and under subatmospheric pressure, (III) continuously adding a neutralizing agent to the reaction mixture of step (II), thereby terminating the polymerization reaction, and (IV) continuously removing the cyclopolysiloxane and volatile components from the reaction mixture.
摘要:
A vibration test system for structures comprises a vibration exciter that vibrates a real model portion, a load meter that measures a load, and a computer that receives a numerical model representing a numerical model portion. The computer includes a block that calculates a displacement, which is made in a predetermined time after completion of measurement, according to a load value and an external force value. A signal production block produces a command signal using as a target value the displacement calculated by the displacement calculation block. A step control block controls the displacement calculation block and signal production block so that they will act cyclically. The displacement calculation block uses an αOS method to time integrate a solution of a vibrational equation.
摘要:
A wood member for a musical instrument, which is capable of preventing occurrence of damage, such as cracking, to thereby ensure smooth and stable operation of the musical instrument and maintain excellent appearance of the same over a long time period. The wood member has compressive internal stress remaining at least in an outer peripheral portion thereof by being subjected to heating processing, cooling processing, and moisture conditioning processing, in advance. A wood workpiece as a workpiece for the wood member is heated at a predetermined temperature, and the heated wood workpiece is cooled. The cooled wood workpiece is subjected to moisture conditioning such that compressive internal stress is generated at least in an outer peripheral portion of the wood workpiece.