JP3432279B2 - Polyethylene succinate resin composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has improved cutting properties in pelletizing a polymer and moldability in injection molding by increasing the crystallization rate of the polymer. The present invention relates to a polyethylene succinate resin composition. 2. Description of the Related Art Plastics used as synthetic fibers, films and other molded articles can be supplied stably at low cost and in large quantities in addition to the advantages of being light and durable.
It has brought richness and convenience to our lives and built a modern society that can be called a plastic civilization. However, in recent years, there has been a demand for the development of a polymer material that can be decomposed in the natural environment in response to environmental problems on a global scale. And high expectations as a new type of functional material. [0003] Aliphatic polyesters produced by melt polycondensation of α, ω-aliphatic diols with α, ω-aliphatic dicarboxylic acids, such as polyethylene succinate (P
ES), polyethylene adipate (PEA) and polybutylene succinate (PBS) are known polymers for a long time, can be manufactured at low cost, and have been confirmed to be biodegradable by microorganisms in soil burial tests. [Int. Biodetetn. Bull., Vol. 11, p. 127 (1
975) and Polymer Science Technology (Po
lym. Sci. Technol.), vol. 3, p. 61 (1973)]. Among them, polyethylene succinate has a melting point of 100 ° C. or higher and excellent biodegradability, but these polymers have poor thermal stability and cause a decomposition reaction at the time of polycondensation. Usually 2,
Only those with a molecular weight of about 000 to 6,000 can be obtained,
It was not enough to process as a fiber or film. [0004] As a method of increasing the molecular weight of these aliphatic polyesters and synthesizing polyethylene succinate having such strength that it can be formed into fibers or films by itself,
A method of treating with diisocyanates such as hexamethylene diisocyanate and toluene diisocyanate [Polym. J., 2, 387 (197)
1) and JP-A-4-189822]
Or polycondensation under a high vacuum of 0.005 to 0.1 mmHg (see JP-A-5-310898)
It is shown. However, polyethylene succinate has a very low crystallization rate (exothermic peak due to slow cooling crystallization by a differential scanning calorimeter cannot be broadly observed at a cooling rate of 20 ° C./min), and the reaction vessel is used. Polyethylene succinate was polycondensed, and even after dispensing after raising the degree of polymerization to the target molecular weight, cutting was not possible using a normal cooling device, and it was possible without installing a long cooling zone There was a problem that the polymer could not be pelletized. Further, when polyethylene succinate having a low crystallization rate such that a peak is not observed even at the above-mentioned low cooling rate is injection-molded, it takes a long time to cool and solidify the polyethylene succinate. However, it was disadvantageous in terms of manufacturing. SUMMARY OF THE INVENTION The present invention relates to a polyethylene succinate having improved cutting properties at the time of pelletizing a polymer and moldability at the time of injection molding without impairing the original property of biodegradability. The present invention provides a resin composition. The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, by mixing a crystallization nucleating agent with polyethylene succinate, the crystallization speed has been greatly increased. The present inventors have found that the above-mentioned problems can be solved and improved, and based on this finding, have reached the present invention. That is, the present invention relates to a polyethylene sac
Crystallization nucleating agent (except acid
Titanium chloride, polyethylene terephthalate, poly-tolan
Excluding scyclohexane dimethanol terephthalate)
Polyethylene succinate containing 0.1 to 50 parts by weight of
The subject matter is a nate resin composition . Hereinafter, the present invention will be described in detail. As the polyethylene succinate used in the present invention,
Any material may be used as long as it has 70 mol% or more of ethylene succinate as a constituent unit. That is, polyethylene succinate may be obtained by substituting a part of the succinic acid component or glycol component with another copolymer component. As the copolymerization component, for example, adipic acid, suberic acid, sebacic acid, dicarboxylic acids such as dodecanoic acid, and, for example, propylene glycol, diethylene glycol,
Trimethylene glycol, hexamethylene glycol,
And diols such as 1,4-cyclohexanedimethanol, 1,4-butanediol, neopentyl glycol, and decamethylene glycol. The polyethylene succinate used in the present invention may be a random copolymer or a block copolymer of one or more components selected from these. In order to obtain such a polyethylene succinate, for example, direct polycondensation may be carried out as disclosed in JP-A-5-310898, or
As disclosed in JP-A-189822, the molecular weight can be increased by using a chain extender such as diisocyanates. In the present invention, it is preferable to select a polyethylene succinate having a reduced specific viscosity of 0.5 or more, more preferably 0.8 or more, measured in chloroform at 30 ° C. according to the intended use. Examples of the crystallization nucleating agent used in the present invention include various conventionally known compounds, for example, inorganic salts such as aluminum silicate, aluminum calcium silicate, calcium phosphate, calcium sulfate and barium sulfate, zinc oxide, and the like. Metal oxides such as magnesium oxide and titanium oxide, clays such as mica, mica, talc, kaolin and clay; organic acid salts such as sodium stearate, calcium stearate, sodium benzoate and zinc salicylate; polypropylene, nylon, polyethylene, etc. And carbon powders such as graphite and carbon black, and boron nitride. These may be used alone or in combination of two or more. Among them, clays such as talc and the like, and boron nitride are particularly preferred because of their high effect of increasing the crystallization rate. [0013] The polyethylene succinate resin composition of the present invention is based on 100 parts by weight of polyethylene succinate.
Comprising 0.1 to 50 parts by weight of a crystallization nucleating agent,
More preferably, it contains 0.2 to 40 parts by weight, particularly preferably 0.5 to 30 parts by weight. If the content of the crystallization nucleating agent is less than 0.1 part by weight, the effect of increasing the crystallization rate tends to be difficult to obtain, and if it exceeds 50 parts by weight, the mechanical properties of polyethylene succinate serving as a matrix are reduced. Tend to lower,
Neither is preferred. These crystallization nucleating agents are preferably dispersed in a very fine state in polyethylene succinate. As a dispersion method of the crystallization nucleating agent, for example,
Examples of the method include a method of charging the raw materials together with the dicarboxylic acid and the diol at the time of polycondensation of polyethylene succinate, a method of mixing polyethylene succinate in a molten state at the end of polycondensation, and a method of melt or dry blending using a kneader. At this time, when polycondensing polyethylene succinate using a reaction vessel, it is desired to mix a crystallization nucleating agent before dispensing in order to pelletize using a normal cooling device. Is the former 2
Is preferred. The polyethylene succinate resin composition of the present invention contains polyethylene succinate and a crystallization nucleating agent as essential components. In addition to the above, various auxiliary additives such as fortified materials may be used according to the application and necessity. Fillers, antioxidants, ultraviolet absorbers, lubricants, release agents, flame retardants, antistatic agents, coloring agents, plasticizers, and the like can be added. Examples of the reinforcing filler in the auxiliary additive include aramid fiber, glass fiber, carbon fiber, asbestos fiber, potassium titanate fiber, and poly-p-phenylene terephthalamide fiber. Further, the amount of the reinforcing filler is preferably in the range of 5 to 150 parts by weight based on 100 parts by weight of polyethylene succinate, and if the amount is less than 5 parts by weight, the imparting of shape stability becomes insufficient. On the other hand, if it is used in excess of 150 parts by weight, the mechanical properties tend to decrease, and both are not preferred. The present invention will be specifically described below with reference to examples. In addition, each value in an Example was calculated | required as follows. (1) Reduced Specific Viscosity (ηsp / c) The viscosity of the polymer solution at a concentration of 0.5 g / deciliter was measured using an Ubbelohde viscometer to obtain a measure of the molecular weight. In addition, it measured at 30 degreeC using chloroform as a solvent. (2) Melting Point and Calorific Value of Crystallization Using a thermal analyzer (DSC-7) manufactured by Perkin-Elmer, the measurement was performed at a heating rate of 20 ° C./min and a slow cooling rate of 20 ° C./min. That is, first, the temperature is raised at a rate of 20 ° C./min and the melting point (T
m) The endothermic peak was measured. After the temperature was further raised to 150 ° C. and held for 5 minutes, the mixture was cooled at a rate of 20 ° C./min, and the exothermic peak (Tc) accompanying crystallization and the exothermic amount (ΔHc) accompanying crystallization were measured. Example 1 In a three-necked flask equipped with a stirrer, a Wigrew fractionating tube, and a gas introducing tube, 47.2 g of succinic acid, 32.3 g of ethylene glycol, and 1.6 g of talc were put, and immersed in a hot water bath. did. The temperature of the water bath was raised to 200 ° C., nitrogen was slowly flowed into the melt, and water and excess ethylene glycol generated at a temperature of 200 ° C. for 3 hours were distilled off to obtain oligomers. Next, 0.1 g of polyphosphoric acid and tetra-n
0.15 g of butoxygermanium is added and the temperature is 22
The white polymer was obtained by heating at 0 ° C. for 2 hours under a reduced pressure of 0.5 mmHg and further for 1 hour at 240 ° C. under a reduced pressure of 0.5 mmHg. The composition has an ηsp / c of 1.02 (concentration of 0.
5 g / deciliter, 30 ° C., in chloroform). When the thermal properties of this polymer were measured, 102
An endothermic peak of melting point (Tm) was clearly observed at ℃, and an exothermic peak (Tc) due to crystallization was clearly observed at 36 ° C, and the calorific value (ΔHc) due to crystallization was 3.0 cal / g. Example 2 3.3 kg of succinic acid and 2.3 kg of ethylene glycol were charged into a small polymerization reactor of 17 liter capacity equipped with a stirrer, a fractionating tube and a gas introducing tube, and the temperature was raised to 200 ° C.
While flowing nitrogen into the melt, the water and excess ethylene glycol generated during 3 hours were distilled off. Next, 3.5 g of polyphosphoric acid and tetra-n
10 g of butoxygermanium was added, the temperature was raised to 240 ° C. over 1 hour, and the mixture was heated under a reduced pressure of 0.5 mmHg for 4 hours to obtain a polymer. Further, after the pressure of the reaction vessel was returned to the atmospheric pressure, 500 g of talc was added to the polymer, and the mixture was stirred until it was uniformly dispersed. After passing through a cooling device (water temperature: 15 ° C.) having a total length of 4.5 m, the tex was cut by a pelletizer (ST type, manufactured by Nakatani Machine Co., Ltd.). As a result, the cutting properties were generally good, and uniform pellets could be obtained. The ηsp / c of this composition is 0.95 (concentration of 0.
5 g / deciliter, 30 ° C., in chloroform), melting point (Tm) is 101 ° C., peak temperature (Tc) accompanying crystallization is 45 ° C., and calorific value (ΔHc) at that time is 10.0 cal / g. Met. Using an injection molding machine (Model 125/75, manufactured by Mitsubishi Heavy Industries, Ltd.), the polymer was heated to a cylinder temperature of 120-1.
Molding was performed at 25-135 ° C, a mold temperature of 30 ° C, and an injection time of 10 seconds, and the minimum cooling time was determined. As a result, the minimum cooling time is 15 seconds, which makes it possible to greatly reduce the molding time during injection molding. Example 3 3.3 kg of succinic acid and 2.3 kg of ethylene glycol were placed in a small polymerization reactor of 17 liter capacity equipped with a stirrer, a fractionating tube and a gas introducing tube, and the temperature was raised to 200 ° C.
While flowing nitrogen into the melt, the water and excess ethylene glycol generated during 3 hours were distilled off. Next, 3.5 g of polyphosphoric acid and tetra-n
10 g of butoxygermanium was added, the temperature was raised to 240 ° C. over 1 hour, and the mixture was heated for 4 hours under a reduced pressure of 0.5 mmHg, so that ηsp / c was 1.12 (concentration 0.5
g / deciliter, 30 ° C., in chloroform) to obtain polyethylene succinate. 100 parts by weight of this polyethylene succinate and 2 parts by weight of boron nitride were mixed by a rotary drum blender, then put into a hopper of a twin screw extruder, melt-kneaded and pelletized. The melting point (Tm) of this composition is 102 ° C., the peak temperature (Tc) accompanying crystallization is clearly observed at 42 ° C., and the calorific value (ΔHc) at that time is 2.2 cal.
/ G. Using an injection molding machine (same as in Example 2), the composition was heated at a cylinder temperature of 120-125-13.
Molded at 5 ° C, mold temperature 30 ° C, injection time 10 seconds,
The minimum cooling time was determined. As a result, the minimum cooling time is 20
Seconds, which makes it possible to significantly reduce the processing time during injection molding. Comparative Example 1 ηsp / c synthesized in Example 3 was 1.12 (concentration: 0.5 g /
Polyethylene succinate (without boron nitride) in deciliters and chloroform) was dispensed out from the lower part of the reaction vessel in a gypsum form while pressurizing with nitrogen. After passing through a water cooling device (water temperature: 15 ° C.) having a total length of 4.5 m, pelletization was attempted, but the polymer was not crystallized and cutting could not be performed. When the thermal properties of this polymer were collected in the form of a tex, and measured, the melting point (Tm) was 103 ° C.
Met. Cooling was continued at a rate of 20 ° C./min to −40 ° C., but no exothermic peak due to crystallization was observed, and at a cooling rate of 20 ° C./min, a peak associated with crystallization was detected broadly. Could not. The polymer was left overnight at room temperature to completely crystallize, and then granulated using a crusher. This granular polymer was molded using an injection molding machine (the same as in Example 2) at a cylinder temperature of 120-125-135 ° C., a mold temperature of 30 ° C., and an injection time of 10 seconds, and the minimum cooling time was determined. As a result, the minimum cooling time is 120 seconds,
A very long cooling time was required, and it took a very long time to cool and solidify. The polyethylene succinate resin composition of the present invention not only enables cutting and pelletizing at the time of dispensing, which was impossible with the conventional polyethylene succinate alone, but also can be used at the time of injection molding. It is very useful because polyethylene succinate retains its original mechanical properties and biodegradability because the molding time can be shortened. The polyethylene succinate resin composition of the present invention is suitable as a material for molding, but can also be widely used as a material for films and fibers.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 63/00-63/91 C08L 67/02

Claims (1)

(57) [Claims] [Claim 1] 100 parts by weight of polyethylene succinate
On the other hand, crystallization nucleating agents (titanium oxide, polyethylene
Terephthalate, poly-transcyclohexanedim
0.1 to 50 parts by weight)
A polyethylene succinate resin composition comprising: