JPH02120320A - Polyester manufacturing method - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for polymerizing polyester, and particularly to a method for producing poly-(trans-1,4-cyclohexylene dimethylene) terephthalate. .

(Prior art and problems to be solved by the invention) Poly-
(Trans-1,4-cyclohexylene dimethylene) terephthalate has a high melting point of 312-318°C, has excellent heat resistance, and is also resistant to hydrolysis, so its use as an engineering plastic is expanding. It is being done.

Conventionally, a combination of a bulk melt polymerization method and a solid phase polymerization method has been used as an industrial method for producing the polyester. However, in the bulk melt polymerization method, the melt viscosity of the polyester increases as the molecular weight increases, so a large stirring power is required. In addition, the polymerization temperature must be higher than the melting point of the polyester (312 to 318°C), so
Normally, a temperature of 340°C or higher is required. However, at this temperature, the polynisder is easily thermally decomposed, and even if it is polymerized over a long period of time, the degree of polymerization does not increase to a level that satisfies practical performance, but rather decreases.

Therefore, in the past, the melt polymerization step took -1
It is taken out in a state where the degree of polymerization is relatively low, and then
A method of in-phase polymerization of pellet-shaped solids has been used, but there is a problem that the polymerization time is extremely long.

(Means for Solving the Problems) The present inventors have already disclosed a method for polymerizing polyalkylene thirefrate in JP-A-60 (1982), in which the polyalkylene thirefrate is heated and polymerized in the form of fine particles in silicone oil using a specific dispersion stabilizer. -1
41714, JP-A-60-141715, and JP-A-62-39621.

In order to solve the above-mentioned problems in the production of poly-(trans-1,4-cyclohexylene dimethylene) terephthalate, intensive studies were conducted regarding the application of this polymerization method to the production of the polymer. When a specific graft polymer is used as a dispersant and polymerization is carried out in silicone oil at a specific polymerization temperature below the melting point of the polyester, the polyester decomposes less and a polyester with a high degree of polymerization can be produced in a short time. A polymerization method that can be obtained has been discovered, and the present invention has been completed.

The gist of the present invention is to use a graft polymer having a polyorganosiloxane as a trunk and a vinyl polymer as a branch, or a graft polymer having a vinyl polymer as a trunk and a polyorganosiloxane as a dispersion stabilizer, to obtain silicone as a dispersion stabilizer. An initial condensate obtained from trans-1,4-cyclohexalinemethanol and terephthalic acid or its derivatives is dispersed in oil in the form of fine particles, and
A method for producing polyester characterized by carrying out heating polymerization at a polymerization temperature of 0°C to 270"C.

The initial condensate obtained from trans-1,4-cyclohexaline methanol and terephthalic acid or its derivative used in the present invention is one that can produce poly-(trans-1,4-cyclohexylene dimethylene) terephthalate. There is no particular limitation if it is. Specifically, trans-1,4-cyclohexaline methanol and dimethyl terephthalate are demethanol-condensed using a transesterification catalyst, or trans-1
, 4-cyclohexaline obtained by dehydration condensation from methanol and terephthalic acid. There are no particular restrictions on the degree of polymerization of the initial condensate, but a degree of 10 or less is preferred for stably dispersing the fine particles.

In addition, this initial condensate contains a small amount of other components, such as cis-1,4-cyclohexalinemethanol within 15mo7% of the diol component, and other aliphatic diols within 10% of the diol component.
Among the acid components, isophthalic acid may be copolymerized within 15 mo1%, and other dicarboxylic acids may be copolymerized within 10 mo1%.

Furthermore, any silicone oil can be used as the silicone oil used in the present invention as long as it is physically and chemically stable at temperatures of 150° C. or higher and does not react with polyester during Bossester polymerization. Examples include polydimethylsiloxane and polydiphenylsiloxane.

Furthermore, the graft polymer used in the present invention is trans-
A dispersing agent necessary for stably dispersing the initial condensate obtained from 1,4-cyclohexalinemethanol and terephthalic acid or its derivatives in silicone oil in the form of fine particles, using polyorganosiloxane as a carrier. It is a graft polymer having vinyl polymer as branches, or a polymer in which the above trunk and branches are interchanged.

The method for producing these graft polymers is not particularly limited, but includes JP-A-60-141741, JP-A-60-141,
No. 715 and Japanese Unexamined Patent Publication No. 62-39621.

The polyorganosiloxane of the above-mentioned graft polymer preferably has as a main constituent a substance close to the structure of the silicone oil used in the present invention, and examples thereof include dimethylsiloxane and diphenylsiloxane as constituent units.

On the other hand, the monomer groups that make up vinyl polymers include (meth)acrylates, aromatic monoalkenyls,
Examples include vinyl cyanide, but (meth)acrylate is preferred. Furthermore, the monomers constituting the (meth)acrylate polymer include alkyl (meth)
The main component is acrylate, and there are functional group-containing (meth)acrylates that can be copolymerized with acrylate, and other components. The number of carbon atoms in the alkyl group of the alkyl (meth)acrylate is not particularly limited, but is preferably 6 or less.

Examples of copolymerizable functional group-containing (meth)acrylates include (meth)acrylates containing carboxyl groups, glycidyl groups, amine groups, hydroxyl groups, amide groups, etc., such as acrylic acid, methacrylic acid, and methacrylic acid. Examples include glycidyl, 2-hydroxyethyl methacrylate, and acrylamide. Further copolymerizable components include styrene, acrylonitrile, and maleic anhydride.

When carrying out the present invention, an initial condensate obtained from trans-1,4-cyclohexalinemethanol and terephthalic acid or a derivative thereof is added to a silicone oil containing a graft polymer containing the above-mentioned polysiloxane as a constituent. , a method of dispersing by shearing, or a method of adding a molten initial condensate to silicone oil, further adding the above-mentioned graft polymer, and dispersing the initial condensate by shearing. The initial condensate becomes a fine particle dispersion due to the action of the polymer.

The particle size of the fine particulate dispersion is determined from the viewpoint of improving the deglycol reactivity of the fine particulate dispersion during polymerization and stabilizing the dispersion of the initial condensate in silicone oil.
Approximately 300 plff or less, especially 0.05 to 150 plff+
It is preferable to keep it within this range.

The amount of the graft polymer that acts as a dispersion stabilizer is not particularly limited, but from the viewpoint of dispersion stabilization, it is preferably 0.1 wt% or more based on the initial condensate.

Polymerization of the fine particulate dispersion involves a deglycol reaction under reduced pressure. The polymerization temperature is preferably 320°C to 270'C. In the method of the present invention, in this temperature range, the fine particles stably exist and the polymerization reaction proceeds rapidly. If the polymerization temperature exceeds 320°C, the decomposition of the polyester will increase, making it impossible to obtain a high polymerization degree of 6. If the polymerization temperature is lower than 270'C, the polymerization rate will drop rapidly, which is not preferred.

In the polymerization of the polyester, a suitable commonly used catalyst is used.

The obtained polyester can be separated from the reaction medium, thoroughly washed with an organic solvent, and then used in the same manner as polyester obtained by conventional bulk melt polymerization.

(Effect of the invention) Conventionally, in the polymerization of polyester, when melt polymerization is performed above the melting point of the resulting polyester, the polymerization rate is fast but it is prone to thermal decomposition, and when a pellet-shaped solid is subjected to in-phase polymerization below the melting point, thermal decomposition can be suppressed. The polymerization rate was very slow.

Surprisingly, with this polymerization method, polymerization can be carried out at a temperature below the melting point of the resulting polyester, and even in that case, the polymerization rate is quite fast, incomparable to conventional in-phase polymerization, and is superior to bulk melt polymerization. Polyester was able to be polymerized at almost the same polymerization rate as that of conventional solid-phase polymerized products.Since the present invention allows polymerization to be performed at such a low polymerization temperature, thermal decomposition of the polyester is suppressed, and the polymerization rate is comparable to that of conventional solid-phase polymerized products. High polymerization degree can be obtained in a short time.

(Example) Hereinafter, the present invention will be specifically explained with reference to Examples.

Reference Example Preparation of Initial Condensate (S-1) Dimethyl terephthalate 500 parts Tetrabutoxytitanium 0.5 parts by weight The raw materials having the above composition were charged into a 312 volume flask equipped with a stirrer, and after being replaced with nitrogen, the temperature was 120 to 280°C. The methanol elimination reaction was carried out for 2 hours while raising the temperature to . The obtained initial condensate, ester compound (S-1), was immediately taken out and cooled.

Production of graft polymer (B-1) 50 parts by weight of cyclic dimethylsiloxane (repeat units 3 to 6), 3 parts by weight of dimethoxy-3-methacryloyloxybrobylmethylsilane and 1 part by weight of methoxytrimethylsilane were added to 0 parts by weight of potassium hydroxide. The reaction system was heated and stirred at 140°C for 3 hours with 0.075 parts by weight in a nitrogen atmosphere at 90°C.
1.3 parts by weight of a 1% aqueous sulfuric acid solution was added thereto, stirred for 1 hour, and then washed with water three times. The water-washed reaction product was distilled to remove unreacted materials to obtain 45 parts by weight of silicone polymer (C).

Next, 70 parts by weight of methyl methacrylate and 1900 parts by weight of toluene were added to 45 parts by weight of this silicone polymer (C).
The mixture was heated and stirred together with 0.0025 parts by weight of benzoyl peroxide at 80° C. for 5 hours under a nitrogen atmosphere. Adding the product to excess acetone to precipitate the graft polymer (B-1),
80 parts by weight were obtained.

Example 1 Ester compound (S-1) 80 parts by weight Silicone oil (polydimethylsiloxane) 120 parts by weight Graft polymer (B-1) 2 parts by weight The raw materials having the above composition were charged into a 500-volume flask equipped with a stirrer. , 8 products were heated to 3000G under a nitrogen atmosphere. Ester compound (S
-1) immediately became a uniform emulsified fine particle state when it melted. Thereafter, polymerization was carried out under vacuum with stirring for 2 hours. The system was extremely stable during and after polymerization.

After cooling the reaction solution, it was washed with toluene to recover the polyester. The polyester is approximately 5 opm pearl-like and has a tetrachloroethane/phenol ratio of 501
25℃, 0.5g measured with a mixed solution of 50 (weight ratio)
The n sp/c of /d7 was 1.2.

Examples 2 to 3, Comparative Examples 1 to 2 Table 1 shows the η sp/c of polyesters obtained by polymerizing under the same conditions as in Example 1 but only changing the polymerization temperature.

From this result, it is clear that polyester with a high degree of polymerization can be obtained only in a specific range of polymerization temperatures.

Table-1 Table-2 Comparative Examples 3 to 5 Using the same polymerization apparatus as in Example 1, ester compound (S-
1) Bulk melt polymerization was carried out by charging 80 parts by weight and changing only the polymerization temperature.

The results are shown in Table-2. It can be seen that when the polymerization temperature is high, the solution viscosity is low and the deterioration is large. Furthermore, it can be seen that stirring becomes impossible when the polymerization temperature is lowered.

Comparative Example 6 The polyester obtained in Comparative Example 5 was collected and
crushed to size. Raise this to 280'C't:'
The flask was placed in a rotary evaporator flask and the pressure was reduced while rotating. After 30 hours, a test sample was taken out. The n sp/c of this polyester is 1.1
Met. This result shows that the polymerization method of the present invention can produce a polymer with a degree of polymerization equivalent to that of in-phase polymerization in an extremely short time.

Supplementary Note: The polyester according to claim 1, wherein the vinyl polymer constituting the graft polymer of the dispersion stabilizer is a (meth)acrylate polymer.

Claims (1)

[Claims] A graft polymer having a polyorganosiloxane as a trunk and a vinyl polymer as a branch, or a graft polymer having a vinyl polymer as a trunk and a polyorganosiloxane as a branch is used as a dispersion stabilizer, and trans-1,4 is added to silicone oil. - A method for producing polyester, which comprises dispersing an initial condensate obtained from cyclohexaline methanol and terephthalic acid or a derivative thereof into fine particles, and heating and polymerizing the resulting particles at a polymerization temperature of 320°C to 270°C.