JPH0449852B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a method for polymerizing polyester, and in particular, it relates to a method for polymerizing polyester, and in particular to a method for polymerizing polyester, in which bis(β-hydroxyethyl) terephthalate (hereinafter referred to as BHT) or an initial condensate thereof is made into fine particles. The present invention relates to a process for making polyesters by polymerization dispersing them in emulsion in active organic liquids.

[Prior art]

Bulk polymerization has been most commonly used to polymerize polyesters such as polyethylene terephthalate. However, in this method, the melt viscosity increases as the molecular weight of the polyester increases, and a large stirring power is required. Furthermore, since the melt viscosity becomes high, heat transfer from the walls of the condensation vessel becomes poor, and local deterioration due to heating tends to occur. In addition, there are some inherent points that should be improved, such as it takes a long time to take out the polymer, and the degree of polymerization differs between the early and late stages of taking out the polymer.

Therefore, the present inventors investigated a method for solving the above problems in polycondensation using BHT or its initial condensate.

BHT or its initial condensate dissolved in a solvent is dispersed in a silicone oil that is non-reactive with BHT or its initial condensate and its solvent using a specific grafted polysiloxane as a medium to form fine particles. They discovered that this method is extremely effective and completed the present invention.

[Structure of the invention]

The gist of the present invention is that a mixture of bis(β-hydroxyethyl) terephthalate or an initial condensate thereof and a solvent is mixed into silicone oil in the form of fine particles to form a grafted polysiloxane having a polysiloxane as a backbone and a polyester oligomer as a branch. A method for polymerizing polyester, characterized by dispersing it as a stabilizer and polymerizing it by heating.

The solvent that dissolves BHT or its initial condensate used in carrying out the present invention is a solvent that becomes liquid at a temperature of 150°C or higher and dissolves BHT or its initial condensate, but has low solubility in silicone oil. Any substance can be used, and specific examples include phenols such as m-cresol, p-chlorophenol, xylenol, and phenol, benzyl alcohol, nitrobenzene, and tetrachloroethane/phenol mixtures. They can be used alone or in combination.

When carrying out the present invention, the above solvent and BHT
BHT or its initial condensate can be efficiently atomized by mixing the mixture and heating it to a temperature of 150° C. or higher to form a substantially uniform solution state and atomizing it.

As the silicone oil used in carrying out the present invention, any silicone oil can be used as long as it is relatively physically and chemically stable even when exposed to high temperatures of 150 to 320°C. .

The grafted polysiloxane used in carrying out the present invention is a dispersion stabilizer necessary to stabilize a mixture of BHT or its initial condensate and a solvent, and its structure has a polysiloxane as a trunk and polyester oligomers as branches. It is. This grafted polysiloxane is produced by condensing an organosilane with a functional group-containing silane, such as γ-glycidoxypropylalkoxysilane, to form a polysiloxane having glycidoxy groups in the side chain, and then using a dicarboxylic acid or a diol. can be reacted with glycidyl groups and then reacted with polyester oligomers, or the polyester oligomers can be directly reacted with glycidyl groups to obtain polysiloxanes grafted with polyester oligomers as branches.

The type of polyester oligomer to be grafted onto the polysiloxane backbone is not particularly limited, but a typical example is an oligomer obtained by direct esterification of terephthalic acid and ethylene glycol, and its molecular weight is about 1000 to 5000. Good to have.

When synthesizing the main polysiloxane, cyclic silane, especially cyclic dimethylpolysiloxane with 3 to 8 repeating units, is used as the main raw material, and one alkoxy in each molecule such as trimethylmethoxysilane or trimethylmethoxysilane is used as a molecular weight regulator. As a functional group-containing silane, a silane compound having a glycidyl group such as γ-glycidoxypropylmethyldiethoxysilane and having two alkoxy groups in one molecule is used. or 100 to 150℃ using a strong base as a catalyst
It is preferable to polymerize with

There are various methods for grafting a polyester oligomer onto a polysiloxane having a functional group such as a glycidyl group in a side chain, but a method of causing a heating reaction with a polyester oligomer is simple.

The molecular weight etc. of the grafted polysiloxane obtained in this way is appropriately determined by taking into consideration its own stability, dispersion stability, and compatibility with polyester or silicone oil, but the molecular weight of the polyester oligomer that becomes the branch The molecular weight of the grafted polysiloxane is preferably about 1,000 to 300,000, which is about the same or lower than the molecular weight of the main polysiloxane. That is, if these molecular weights are too small, the compatibility with polyester or silicone oil will be insufficient, and if the molecular weights are too large, the probability of thermal deterioration will increase and the dispersion stability during polyester polymerization will decrease. Therefore, it is not desirable. Further, the weight ratio of polysiloxane to polyester oligomer in the grafted polysiloxane is appropriately selected in consideration of dispersion stability, etc., and is particularly preferably about 1:1.

When carrying out the present invention, BHT or its initial condensate mixed with a solvent is added to a silicone oil containing a grafted polysiloxane, and the mixture is dispersed into an emulsion by shearing, or
A method of forming an emulsion by dropping a mixture of a solution of BHT or its initial condensate and a graft polymer while stirring silicon oil at high speed, and further using a homogenizer to form an emulsion containing uniform fine particles. be able to.

The particle size of the fine particles made of a mixture of BHT or its initial condensate and a solvent is 100μ or less, especially 0.05~
A range of 80μ is more desirable because it allows efficient diffusion of ethylene glycol from the particulates to the interface of the particulates.
It is also desirable from the viewpoint of stabilizing the emulsion of fine particles of the initial condensate.

Polyesterification of BHT or its precondensate can be carried out without a catalyst or in the presence of a suitable catalyst.

The obtained polyester can be separated from the reaction medium and thoroughly washed with an organic solvent, and then further subjected to a polymerization reaction. The silicone oil separated from the reaction system is filtered, and after ethylene glycol is distilled off, it is recycled back to the reaction system for use.

The grafted polysiloxane has a structure in which the branch polyester oligomer is placed on the particulate side and the trunk polysiloxane is placed on the silicone oil side at the interface between the particulates and the silicone oil, thereby achieving a dispersion effect. It is estimated that it is increasing.

Furthermore, because a specific grafted polysiloxane is used as a dispersion medium for a mixture of BHT or its initial condensate and a solvent in silicone oil.
Fine particles of a mixture of BHT or its initial condensate and a solvent are stably and uniformly dispersed in silicone oil, which also contributes to the promotion of the polyesterification reaction.

The method of the present invention is not limited to the production of polyethylene terephthalate, but also polybutylene terephthalate,
Alternatively, it can be fully utilized in the production of copolymerized polyester.

The present invention will be explained in more detail with reference to Examples below.

All parts and percentages are by weight.

Reference Example - Production of grafted polysiloxane - With the aim of obtaining a polysiloxane with a molecular weight of about 8000, 50 parts of cyclic dimethylpolysiloxane (3 to 6 repeating units), 3 parts of γ-glycidoxypropylmethyldiethoxysilane, and 1 part of methoxytrimethylsilane was stirred with 0.0075 part of potassium hydroxide at 140° C. for 3 hours under a nitrogen atmosphere. The reaction system was cooled to 90°C, 1.3 parts of a 1% aqueous sulfuric acid solution was added, stirred for 1 hour, and then washed with water three times. The water-washed reaction product was distilled to remove unreacted materials, yielding 47 parts of silicone polymer A.

Example 1 Dispersion of fine particles of polyethylene terephthalate oligomer solution in silicone oil Polymer A1 part obtained in Reference Example and polyethylene terephthalate oligomer ([η]) obtained by direct polycondensation of terephthalic acid and ethylene glycol.
A portion of the polyethylene terephthalate oligomer was graft-polymerized onto Polymer A by heating 20 parts of polyethylene terephthalate oligomer (=0.1) and 0.009 parts of antimony trioxide together with 80 parts of parachlorophenol at 180° C. for 1 hour under stirring in a nitrogen atmosphere. 100 parts of the mixture thus obtained was placed in 400 parts of silicone oil (dimethylpolysiloxane type, Toray SRX-310) heated to 200°C while maintaining the temperature at 180°C, and heated to 200°C under stirring in a nitrogen atmosphere. for 6 hours, then
The temperature was raised to 240°C at a heating rate of 0.5 deg/min, and the temperature was further maintained at 240°C for 2 hours.

As soon as the mixture was poured into silicone oil, a dispersion of fine particles formed.

The microparticles remained stable during stirring.

After cooling, the silicone oil was filtered and collected, and the intrinsic viscosity [η] of the polymer was 0.31.

Example 2 Dispersion of fine particles of polyethylene terephthalate oligomer solution in silicone oil Polymer A1 part obtained in Reference Example and polyethylene terephthalate oligomer ([η]) obtained by direct polycondensation of terephthalic acid and ethylene glycol.
= 0.1) 20 parts and 0.009 parts of antimony trioxide were mixed with 80 parts of xylenol at 180°C under stirring in a nitrogen atmosphere.
A part of the polyethylene terephthalate oligomer was graft-polymerized onto Polymer A by heating for 1 hour. The mixture thus obtained
While keeping 100 parts at 180°C, put it into 400 parts of silicone oil (dimethylpolysiloxane type, Toray SRX-310) heated to 197°C, keep it at 197°C for 6 hours under stirring in a nitrogen atmosphere, and then 0.5 deg. /min
The temperature was increased to 240℃ at a heating rate of
Holds time.

As soon as the mixture was poured into silicone oil, a dispersion of fine particles formed.

The microparticles remained stable during stirring.

After cooling, the silicone oil was filtered and collected, and the intrinsic viscosity [η] of the polymer was 0.30.

Example 3 Dispersion of fine particles of polyethylene terephthalate oligomer solution in silicone oil 1 part of polymer A obtained in Reference Example and 20 parts of polyethylene terephthalate oligomer ([η] = 0.1) obtained by direct polycondensation of terephthalic acid and ethylene glycol A portion of the polyethylene terephthalate oligomer was graft-polymerized onto Polymer A by heating 0.009 parts of anticene trioxide and 80 parts of metacresol at 180°C for 1 hour under stirring in a nitrogen atmosphere. 100 parts of the mixture thus obtained was placed in 400 parts of silicone oil (dimethylpolysiloxane type, Toray SRX-310) heated to 197°C while maintaining the temperature at 180°C, and heated to 197°C under stirring in a nitrogen atmosphere. for 6 hours, then
The temperature was raised to 240°C at a heating rate of 0.5 deg/min, and the temperature was further maintained at 240°C for 2 hours.

As soon as the mixture was poured into silicone oil, a dispersion of fine particles formed.

The microparticles remained stable during stirring.

After cooling, the silicone oil was filtered and collected, and the intrinsic viscosity [η] of the polymer was 0.28.

Claims (1)

[Claims] 1. A mixture of bis(β-hydroxyethyl) terephthalate or an initial condensate thereof and a solvent is dispersed in silicone oil, and a grafted polysiloxane having a polysiloxane as a backbone and a polyester oligomer as a branch is used as a dispersion stabilizer. Dispersed into fine particles as
A polyester polymerization method characterized by heating polymerization. 2. The method for polymerizing polyester according to claim 1, wherein the particle size of the fine particles of the mixture of bis(β-hydroxyethyl) terephthalate or its initial condensate and a solvent is 100 μm or less.