JPH0513813B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing polytriorganovinylsilane molded products, particularly films and thin plates that have significantly improved mechanical strength and improved durability without impairing transparency. The present invention relates to a method for producing polytriorganovinylsilane molded products useful for fibers and the like. (Prior Art) Polytriorganovinylsilane obtained by polymerizing triorganovinylsilane has excellent transparency, and this also means that its oxygen permeability coefficient is
It has the advantage of being large at 4.5×10 ^-9 cm ³ (STP) cm/cm ² sec cmHg. However, molded products made from polytriorganovinylsilane have low mechanical strength and are relatively brittle, which limits their use. Although it has been found that mechanical strength can be improved, the effect is not sufficient, and no effective method for imparting strength has yet been found, especially for molded products such as films, thin plates, and fibers. However, its brittleness has not been sufficiently improved, and its applications are limited. (Structure of the Invention) The present invention solves these disadvantages and relates to a method for producing a polytriorganovinylsilane molded article, which has the formula (Here, R ¹ , R ² , R ³ are alkyl groups having 1 to 6 carbon atoms or phenyl groups, and n is a positive number of 600 or more.) It is characterized by uniaxial or multiaxial stretching or rolling at high temperatures. That is, as a result of various studies on methods for improving the mechanical strength, particularly the brittleness, of polytriorganovinylsilane molded products, the present inventors found that primary molded products molded according to conventional methods were heated to temperatures higher than the heat softening temperature. We have discovered that mechanical strength such as tensile strength, bending strength, and impact strength of this molded product can be greatly improved by stretching or rolling it at a temperature range lower than the melting temperature. The present invention was completed by conducting research on temperature ranges, etc. The polytriorganovinylsilane used as an initiator in the method of the present invention has the formula R ¹ , R ² , and R ³ are alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, propyl, butyl, or phenyl groups; If the n value is less than 600, the mechanical strength will be insufficient and it will be impossible to manufacture a primary molded product, so it must be a positive number of 600 or more. This polytriorganovinylsilane has the formula It can be obtained by adding n-butyllithium as a catalyst to the triorganovinylsilane represented by and anionically polymerizing it in an inert gas atmosphere at a temperature of 20 to 70°C for 20 to 50 hours. It may be a homopolymer thereof, or a copolymer with a comonomer copolymerizable with the above-mentioned triorganovinylsilane, such as siloxanes such as dimethylsiloxane, isoprene, or styrene. It is preferable that the organovinylsilane content be 70 mol% or more. The heat softening temperature of this polytriorganovinylsilane primary molded product varies from 90°C to 170°C depending on the types of R ¹ , R ² , and R ³ and the n value, but it is usually 180°C to 340°C. This can be heated to a temperature range of It is preferable to use a body, a block body, a film, a rod-shaped body, or a cylindrical body. In the method for producing a polytriorganovinylsilane molded article according to the present invention, the primary molded article thus obtained is stretched or rolled, and this stretching and rolling may be carried out using known equipment.
However, the temperature at which stretching and rolling is performed is determined by the above equation (1).
When R ¹ , R ² , and R ³ are all alkyl groups, the thermal softening temperature of this product is 130°C to 160°C,
Since the melting temperature is 230°C to 330°C, the temperature range is preferably 140°C to 170°C, and if R ¹ , R ² , and R ³ contain a phenyl group, the thermal softening temperature is 85°C.
~115℃, and the melting temperature is 200℃ to 300℃, so it is best to carry out in the temperature range of 90 to 120℃.
Below these temperature ranges, the polymer will not soften sufficiently and cannot be stretched or rolled, and if the temperature is higher than this temperature range, the strength-imparting effect will not be sufficiently exerted even when stretched or rolled. Heating for stretching or rolling this primary molded body is preferably carried out in an inert gas or polyethylene glycol bath; heating in air for several hours may cause a decrease in the degree of polymerization of the polymer. Therefore, it is not desirable. The method of stretching or rolling, whether uniaxial or multiaxial, can be selected as appropriate depending on the purpose, but in order to impart strength more effectively, stretching is recommended, and rod or fiber It is preferable to use uniaxial stretching for forming shaped objects, and biaxial stretching for films or plate-like objects, but in this case, the stretching ratio, stretching speed, etc. can be selected appropriately depending on the purpose and shape of the molded product. good. In addition, in order to improve the shape stability of the molded product after this stretching or rolling, it is preferable to perform a secondary heat treatment, and the temperature of this secondary heating may be in the range of 100 to 170°C. Molded products of polytriorganovinylsilane obtained by the method of the present invention are useful as materials for optical materials such as optical lenses and contact lenses, and materials for plastic optical fibers. Next, examples of the present invention will be given. Example 1, Comparative Example 1 Formula

Add 0.1 ml of a hexane solution of n-butyllithium at a concentration of 15% to 50 g of trimethylvinylsilane represented by the formula, and anionically polymerize the mixture at 50°C for 70 hours in an anhydrous nitrogen gas atmosphere. The resulting polymer is dissolved in 500 ml of cyclohexane. After purification by precipitation in excess methanol and drying, 46 g of polytriorganovinylsilane with a molecular weight of 510,000 was obtained. Then, this polymer was dissolved in toluene and 25
% by weight toluene solution, a plate with a thickness of 0.8 mm was made from it by the casting method, and then this
Heat a 100mm square plate to 155℃ and heat each side to 100mm.
Biaxially stretched at the same time at a stretching speed of mm/s, and the stretching ratio
1.45×1.45x (2.1x), 2.0x2.0x (4.0x), 3.0x
A 3.0x (9.0x) transparent stretched film was produced. Next, these stretched films were subjected to a secondary heat treatment for 60 minutes in a polyethylene glycol bath at 130°C, and then the tensile strength and elongation at break of these stretched films and an unstretched film prepared for comparison were measured at 25°C. The results were obtained as shown in Table 1 when measurements were carried out according to the method of JIS K7113 under conditions of a tensile speed of 10 mm/min. In addition, in order to evaluate the impact strength of these stretched films, a film with a width of 10 mm was
A steel ball of 85 g is dropped from the top held horizontally with no slack at intervals of mm, and the falling height of the steel ball when the film breaks is measured, and for comparison, the same thickness as this stretched film is measured. An unstretched film of It was confirmed that mechanical strength, especially impact strength, was significantly improved and brittleness was improved.

【table】

[Table] Examples 2 to 5 The following four monomers were used instead of the trimethylvinylsilane homopolymer in Example 1. were used and treated in the same manner as in Example 1 to produce the four types of polymers shown in Table 3. These polymers were then subjected to casting treatment in the same manner as in Example 1 to produce films with a thickness of 0.8 mm, and these were stretched at the stretching temperature shown in Table 3 to 2.0 mm.
×2.0 times (4.0 times) biaxial stretching, and the tensile strength at break, elongation at break, and fall height at break by falling ball method of the obtained stretched film and unstretched film were measured in the same manner as in Example 1. The results shown in Table 3 were obtained.

【table】

Claims (1)

[Claims] 1 formula (Here, R ¹ , R ² , R ³ are alkyl groups having 1 to 6 carbon atoms or phenyl groups, and n is a positive number of 600 or more.) A method for producing a polytriorganovinylsilane molded product, which comprises uniaxially or multiaxially stretching or rolling at a temperature. 2. The polyester resin according to claim 1, wherein a primary molded product of polytrialkylvinylsilane in which R ¹ , R ² , and R ³ are alkyl groups having 1 to 3 carbon atoms is stretched or rolled at a temperature of 140 to 170°C. A method for producing triorganovinylsilane molded products. 3 A primary molded product of polytriorganovinylsilane in which any one of R ¹ , R ² , and R ³ is a phenyl group is
A method for producing a polytriorganovinylsilane molded article according to claim 1, which comprises stretching or rolling at a temperature of ~120°C.