JPH0225932B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polybutylene terephthalate polymer particles. For more details,
The present invention relates to a method for producing highly crystalline polybutylene terephthalate polymer particles using lactam. Polyesters such as polybutylene terephthalate polymers, which contain terephthalic acid and 1,4-butanediol as essential components, can be used in a variety of fields by taking advantage of their excellent physical properties such as crystallinity, chemical properties, and thermal properties. For example, it is used in injection molded products, fibers, films, etc. However, when using such polyester in applications such as polymer nucleating agents that require highly crystalline fine particles, it is not only difficult to pulverize it due to its excellent physical and chemical properties, but also the highly crystalline fine particles The problem is that it cannot be obtained. For example, mechanical pulverization is suitable for coarse pulverization, but not only is there a limit to pulverization, but also highly crystalline fine particles cannot be obtained. In addition, a method is known in which halogenated aromatics are heated and dissolved in a specific solvent, and then cooled and precipitated to form a fine powder.
This method has the drawback that the polymer precipitation rate during cooling precipitation is extremely slow and that it takes an extremely long time to form fine particles with good yield. Therefore, the present inventors conducted various studies on a method for producing highly crystalline fine particles of a polybutylene terephthalate polymer. As a result, the present inventors discovered a method for producing highly crystalline fine particles of a polybutylene terephthalate polymer by heating and dissolving the polybutylene terephthalate polymer in lactam and then cooling it. The inventors have discovered that polybutylene terephthalate-based fine particles can be obtained, and have arrived at the present invention. That is, the present invention provides a method for producing polybutylene terephthalate polymer fine particles, which comprises dissolving the polybutylene terephthalate polymer in a lactam having the following general formula and then precipitating the polybutylene terephthalate polymer fine particles. It provides: (R in the above formula is an alkyl group having 1 to 5 carbon atoms or an H atom, and n is an integer of 1 to 10.) In the present invention, the polybutylene terephthalate polymer refers to terephthalic acid and 1,4-butanediol. It is a polymer that is an essential component. up to 50 mol %, more preferably 30 mol %, further consisting of other dicarboxylic acids and/or other diols.
Although it can contain up to mol% of copolymerized components,
If the copolymerization component exceeds 50 mol%, it is not preferable because it not only impairs the excellent physical properties of polybutylene terephthalate but also reduces crystallinity, making it impossible to apply the method of the present invention. Dicarboxylic acids other than terephthalic acid include isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid,
Aromatic dicarboxylic acids 1,4 such as diphenyl-4,4'-dicarboxylic acid, diphenoxyethane dicarboxylic acid, sodium 3-sulfoisophthalate, etc.
- cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid, succinic acid, oxalic acid, adipic acid,
Examples include aliphatic dicarboxylic acids such as sebacic acid, dodecanedioic acid, and dimer acid. Of course, ester-forming derivatives of dicarboxylic acids such as lower alkyl esters, aryl esters,
Carbonic esters, acid halides, and the like can be equally used. Diol components other than 1,4-butanediol include aliphatic diols such as ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, and decamethylene glycol, and 1,1-cyclohexane diol. Alicyclic diols such as methanol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, xylylene glycol, bis(p-
hydroxy) diphenyl, bis(p-hydroxyphenyl)propane, 2,2-bis[4-(2-
hydroxyethoxy)phenyl]propane, bis[4-(2-hydroxy)phenyl]sulfone,
1,1-bis[4-(2-hydroxyethoxy)
Examples include diols containing aromatic groups such as [phenyl]cyclohexane. Such diols can also be used in the form of ester-forming derivatives such as acetyl derivatives, alkali metal salts, and the like. The polybutylene terephthalate polymer may be produced by a known method. For example, a lower alcohol diester of a dicarboxylic acid or an excess amount of a low molecular weight glycol may be transesterified in the presence of a catalyst, and the resulting reaction product may be polycondensed, or a dicarboxylic acid and a glycol may be esterified in the presence of a catalyst. A method in which polybutylene terephthalate is prepared in advance, and then other dicarboxylic acids or diols are added to it, or other copolymerized polyesters are added and randomization is performed by transesterification. Either method may be used. As a common catalyst for transesterification or esterification reactions and polycondensation reactions, titanium catalysts give good results. Particularly preferred are tetraalkyl titanates such as tetrabutyl titanate and tetramethyl titanate, and metal salts of titanium oxalate such as potassium titanium oxalate. Other catalysts include tin compounds such as dibutyltin oxide and dibutyltin laurate, and lead compounds such as lead acetate. Furthermore, a polycarboxylic acid, a polyfunctional hydroxy compound, an oxyacid, or the like may be copolymerized as part of the dicarboxylic acid or glycol. The polyfunctional component effectively acts as a viscosity increasing component, and the range in which it can be copolymerized is 3 mol % or less. Examples of compounds that can be used as such polyfunctional components include trimellitic acid, trimesic acid, pyromellitic acid, penzophenonetetracarboxylic acid, butanetetracarboxylic acid, glycerin, pentaerythritol and their esters and acid anhydrides. can. When the method of the present invention is applied to polyesters other than the above-mentioned polybutylene terephthalate-based polymers, for example, polyethylene terephthalate, it is possible to make them into fine particles, but fine particles as highly crystalline as the polybutylene terephthalate-based polymer cannot be obtained. By applying the present invention to a terephthalate polymer, it becomes possible to obtain highly crystalline fine particles that can be used as a nucleating agent, thereby achieving the present invention. The lactam of the present invention is a compound of the following general formula, (R in the above formula is an alkyl group having 1 to 5 carbon atoms or an H atom, and n is an integer of 1 to 10.) Specifically, β-propiolactam, γ-butyrolactam, γ-valerolactam, δ- Examples include valerolactam, ε-caprolactam, heptolactam, etc., and these may be used alone or in combination of two or more. In addition, many other solvents that have heat resistance and boiling point that do not cause operational problems during heating and dissolution, and are compatible with the above-mentioned lactams may be used in combination. The method of dissolving the polybutylene terephthalate polymer in the lactam is arbitrary and is not particularly limited. Add the mixture and heat for 5 to 30 minutes to dissolve. The melting temperature is not particularly limited as it changes depending on the composition of the polybutylene terephthalate polymer and the amount added, but a temperature of 150° C. to the boiling point of the lactam is preferred. In addition, various additives may be added during dissolution, such as forming aids such as known crystal nucleating agents and lubricants, known antioxidants, heat-resistant and light-resistant stabilizers such as ultraviolet absorbers,
Hydrolysis resistance improvers, colorants (pigments, dyes), antistatic agents, conductive agents, flame retardants, reinforcing agents, fillers, plasticizers, mold release agents, etc. can be optionally added and dissolved and incorporated into fine particles. . In particular, the heat aging resistance can be improved by using a known heat stabilizer such as a hindered phenol type or an amine type heat stabilizer. Further, by adding talc or the like as a known crystal nucleating agent, it becomes possible to produce finer particles. In this case, the amount added is preferably 0.005 to 5.0% by weight based on the total weight of the polybutylene terephthalate polymer and lactam. In the method of the present invention, the shape, crystallinity, etc. of the fine particles can be changed depending on the process of cooling the lactam solution in which the polybutylene terephthalate polymer is dissolved and precipitating the polybutylene terephthalate polymer. For example, by slowing down the cooling rate and precipitating at a high temperature, large spherulite particles can be obtained, and by rapid cooling, small spherulite particles can be obtained. Furthermore, if the particles are precipitated while applying shear, it is possible to produce randomly shaped and highly crystalline fine particles. Furthermore, it is possible to produce fine particles having any degree of crystallinity, shape, and particle size distribution by precipitating while applying pressure, and all of these are included within the technical scope of the present invention. The slurry or solid containing the polybutylene terephthalate polymer cooled as described above is then overdried after dissolving the lactam in a solvent such as water to obtain fine particles of the polybutylene terephthalate polymer. . The solvent used at this time is not particularly limited, and any solvent may be used as long as it dissolves the lactam at around room temperature and does not dissolve the polybutylene terephthalate polymer. Furan etc. can be mentioned. The polybutylene terephthalate polymer particles of the present invention can be used for various purposes, such as resin powder for powder coating, fillers, suspensions, and nucleating agents for molding. It can be applied to many uses through physical processing. The present invention will be explained below with reference to Examples. In the examples, all percentages expressed as "%" are expressed as weight ratios. Further, the logarithmic viscosity shown in the text and examples is a value measured in orthochlorophenol at 30°C and at a concentration of 0.5%. Further, the degree of crystallinity in the examples was determined from the ratio of the total scattering intensity to the crystal scattering intensity using a wide-angle X-ray scattering device manufactured by Rigaku Denki. In addition, the particle shape and size distribution was determined from microscopic observation. Examples 1 to 8, Comparative Example 1 Polybutylene terephthalate with a logarithmic viscosity of 0.60 obtained from terephthalic acid and 1,4-butanediol was added in the weight percent shown in Table 1 to ε-caprolactam heated to 210°C under stirring. , heated for about 15 minutes to dissolve. After dissolution, the solution was cooled to room temperature using the precipitation method shown in Table 1. Distilled water was added to the obtained solid to dissolve ε-caprolactam, followed by filtration, washing with water, and drying to obtain polybutylene terephthalate fine particles. Table 1 shows the properties of the obtained polybutylene terephthalate fine particles. For comparison, the properties of mechanically pulverized polybutylene terephthalate powder are also included.
This powder was obtained by pulverizing a pelleted sample in a pulverizer for one hour while cooling it with liquid nitrogen, and then passing it through a 100-mesh sieve. 【table】

Claims (1)

[Scope of Claims] 1. A method for producing polybutylene terephthalate polymer particles, which comprises dissolving a polybutylene terephthalate polymer in a lactam having the following general formula and then precipitating the polybutylene terephthalate polymer particles. (R in the above formula is an alkyl group having 1 to 5 carbon atoms or an H atom, and n is an integer of 1 to 10.)