JP2016020551A - Method for producing resin molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin molded body containing little foreign matter such as a fish eye, and having excellent extrusion moldability, product appearance and the like, specifically a spun resin fiber.SOLUTION: Provided is a resin molded product, which has excellent extrusion moldability, product appearance and the like, especially excellent spinnability and film processability, produced by extrusion molding processing using a polyacetal resin, a polymer having an aliphatic ester structure, and a compound having reactivity with a carboxyl group, the polyacetal resin having a number of fish eyes having a long axis length of 30 μm or less decreased to 5 or less in a 5 cm square film when filtered through a filter installed on a breaker plate and molded into a film of 30 μm thickness. The polymer having an aliphatic ester structure is polylactic acid, polyester carbonate, polybutylene succinate or polybutylene succinate adipate. The compound having reactivity with a carboxyl group includes at least one or more selected from oxazoline compounds, carbodiimide compounds, epoxy compounds, and amide compounds.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a resin molded body that has few foreign matters such as fish eyes and is excellent in extrusion moldability, product appearance, and the like.

In recent years, attention has been paid to the use of biodegradable (microbial degradable or naturally degradable) materials to prevent industrial waste from polluting the environment against global environmental problems. Yes. Furthermore, in recent years, voluntary regulations on CO ₂ emissions associated with global resource depletion and global warming have been strongly demanded. In addition, materials derived from natural products, not oil, and the amount of heat and CO ₂ generated during incineration A small amount of material is drawing attention.
Conventionally, it is known that a polymer having an aliphatic ester structure is biodegradable, and poly-3-hydroxybutyric acid ester (PHB) produced by microorganisms, polycaprolactone (PCL) which is a synthetic polymer The main raw material is polybutylene succinate (PBS) or polybutylene succinate adipate (PBSA) mainly composed of succinic acid and butanediol, and L-lactic acid and / or D-lactic acid produced by fermentation. A typical example is polylactic acid (PLA).
Except for PLA, these polymers having an aliphatic ester structure are generally polymers having physical properties similar to polyethylene and good moldability and biodegradability. However, it does not have sufficient strength in fields that require rigidity and fields that require tensile strength. In order to improve the rigidity, it is possible to improve by using a filler such as talc or a nanocomposite technology, but there is a problem of a decrease in fluidity, and this improvement has been desired. For PLA, improvement of heat resistance and hydrolysis resistance is strongly demanded.

On the other hand, a polymer having an oxymethylene structure is an aliphatic ether type or a polymer mainly composed of an aliphatic ether, and is derived from methanol, which is a raw material independent of petroleum, and is considered to be a material with low environmental impact. . It has excellent mechanical properties such as rigidity and is an excellent material used as engineering plastics. However, there is a demand for a higher level of rigidity and toughness as market needs, and since the crystallinity is high, the moldability to films and fibers is poor, and an improvement thereof has been desired.
Our company has practically sufficient heat resistance by mixing a polymer having an aliphatic ester structure and a polymer having a specific oxymethylene structure, and has rigidity, toughness, heat resistance, moldability, and biodegradability. Have found a resin composition comprising a polymer having an aliphatic ester structure and a polymer having a specific oxymethylene structure (see Patent Document 1). There is a demand for improvement, reduction of foreign matters during molding of product appearance, fish eyes, and the like.
In Patent Document 2, attempts have been made to improve heat resistance and hydrolysis resistance by melting and kneading a carboxyl group-reactive end-blocking agent to polylactic acid resin and polyacetal resin. There is no description regarding the product appearance of the film, and there is no specific suggestion about the fish eye generated in the molded product.

JP 2008-38040 A JP 2003-321602 A

  An object of the present invention is to produce a resin molded body having few foreign matters such as fish eyes and excellent in extrusion moldability, product appearance and the like.

  As a result of intensive investigations by the present inventors to solve the above problems, a filter is installed on the breaker plate, and the polyacetal resin and the aliphatic ester structure are obtained by filtering the number of fish eyes to a certain amount or less. When extrusion molding is carried out using a polymer, it has been found that it is excellent in extrudability, product appearance, etc., in particular, excellent in spinnability and film processability, and has led to the completion of the present invention.

  The method for producing a resin molded body of the present invention makes it possible to produce a molded body having excellent extrusion moldability, product appearance, and the like. In particular, it has excellent spinnability and little optical unevenness when formed into a film or sheet.

The polyacetal resin used in the method for producing a resin molded body of the present invention is a polymer compound having an oxymethylene group (—OCH ₂ ) as a main constituent unit, and substantially consists only of repeating oxymethylene units. Or a polyacetal copolymer containing at least one other comonomer unit in addition to polyoxymethylene and oxymethylene units is a typical resin.
Furthermore, the polyacetal resin may be a conventional polyacetal resin, for example, a copolymer in which a branched structure or a crosslinked structure is introduced by copolymerizing a branch-forming component or a crosslinking-forming component, and further a repeating oxymethylene group. Also included are block copolymers and graft copolymers having units. These polyacetal resins can be used alone or in combination of two or more.

  As the comonomer that is a raw material of the polyacetal resin, cyclic formal or ether is used. For example, 1,3-dioxolane, 2-ethyl-1,3-dioxolane, 2-propyl-1,3-dioxolane, 2-butyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane, 2 -Phenyl-2-methyl-1,3-dioxolane, 4-methyl-1,3-dioxolane, 2,4-dimethyl-1,3-dioxolane, 2-ethyl-4-methyl-1,3-dioxolane, 4, 4-dimethyl-1,3-dioxolane, 4,5-dimethyl-1,3-dioxolane, 2,2,4-trimethyl-1,3-dioxolane, 4-hydroxymethyl-1,3-dioxolane, 4-ptyl Oxymethyl-1,3-dioxolane, 4-phenoxymethyl-1,3-dioxolane, 4-chloromethyl-1,3-dioxolane, 1,3-dioxabicyclo 3,4,0] nonane, ethylene oxide, propylene oxide, Petit alkylene oxide, shrimp chlorohydrin, styrene oxide, Okishitan, 3,3-bis (chloromethyl) oxetane, tetrahydrofuran, and oxepane, and the like. Of these, 1,3-dioxolane is particularly preferred.

  The blending amount of the comonomer is preferably 0.2 to 50 parts by weight, more preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of trioxane. When the amount of the comonomer is more than 50 parts by weight, the polymerization yield is lowered, and when it is less than 0.2 parts by weight, the thermal stability is lowered.

The production method of the polyacetal resin used in the present invention is not particularly limited, and is generally a method in which trioxane and a cyclic ether compound or a cyclic formal compound as a comonomer are bulk polymerized mainly using a cationic polymerization catalyst. Can be obtained. As the polymerization apparatus, any known apparatus such as a continuous type and a batch type can be used.
The polyacetal resin in which the polymerization catalyst has been deactivated is granulated by kneading various stabilizers, heat-melting treatment, thermally decomposing and removing unstable structures. Typical stabilizers include hindered phenol compounds, nitrogen-containing compounds, alkali or alkaline earth metal hydroxides, inorganic salts, carboxylates, and the like.

  Furthermore, for the polyacetal resin, a colorant, a nucleating agent, a plasticizer, a fluorescent brightening agent, or a release agent such as a fatty acid ester or silicon compound such as pentaerythritol tetrastearate, or a sliding agent, if necessary. Additives such as antistatic agents such as polyethylene glycol and glycerin, higher fatty acid salts, ultraviolet absorbers such as benzotriazole or benzophenone compounds, or light stabilizers such as hindered amines may be added as desired. it can.

  Examples of the polymer having an aliphatic ester structure used in the method for producing a resin molded body of the present invention include aliphatic polyesters such as PHB, PCL, PBS, PBSA, PLA, and aliphatic polyester carbonate. Among these, PLA is particularly preferable.

  PLA in the present invention is a polymer mainly composed of any one of L-lactic acid, only D-lactic acid, and a mixture of L-lactic acid and D-lactic acid, or a mixture thereof. A polymerization component may be included. Other monomer units include cyclic lactones such as ε-caprolactone, α-oxy acids such as α-hydroxyisobutyric acid and α-hydroxyvaleric acid, glycol compounds such as ethylene glycol, propylene glycol, and 1,4-butanediol. And dicarboxylic acids such as succinic acid, oxalic acid, adipic acid and sebacic acid. Among these, glycols and cyclic lactones are preferable.

As a polymerization method of PLA, a known polymerization method can be used, and examples thereof include a direct polymerization method from lactic acid and a ring-opening polymerization method via lactide. The ring-opening polymerization method can be obtained by ring-opening polymerization of L-lactide and further a copolymerization component (comonomer or oligomer) in the presence of a catalyst, and reprecipitation purification as necessary.
The molecular weight and molecular weight distribution of PLA are not particularly limited, but the number average molecular weight is preferably 10,000 or more, more preferably 50,000 or more.
The melting point of PLA is not particularly limited, but is preferably 120 ° C. or higher, and more preferably 150 ° C. or higher.

  The blending ratio of the polyacetal resin and the polymerization having an aliphatic ester structure is 1/99 to 99/1 by weight ratio (polyacetal resin / polymerization having an aliphatic ester structure), preferably 5/95 to 95 /. 5, more preferably 60/40 to 95/5.

  The polyacetal resin used in the method for producing a resin molded body of the present invention and a polymer component having an aliphatic ester structure can be mixed in advance. In addition, a mixed resin composition of a polyacetal resin and a polymer having an aliphatic ester structure can be obtained by mechanically mixing at least at a temperature at which at least one resin melts, and both resins are mechanically mixed. It is possible to manufacture by mixing and pressurizing the pulverized material, or by obtaining both by dissolving both resins in a solvent and then mixing with a poor solvent and precipitating, but it is not limited to them. It is not something.

Although it does not specifically limit about a mixing apparatus, It is industrially recommended that the method of mixing using an extruder can be processed continuously in a short time.
When the mixing temperature is 100 ° C. or lower, the resin has a high melt viscosity or does not melt. Specifically, the range of 100 ° C. to 300 ° C. is preferable. A temperature of 300 ° C. or higher is not preferable because thermal decomposition of the resin occurs. Even if it is 300 ° C. or lower, it is preferable to mix in a short time in a nitrogen atmosphere in order to prevent coloring, deterioration, thermal decomposition, etc. A specific mixing time of 20 minutes or less is recommended. It is also possible to install a vent port and remove the mixture under reduced pressure in order to remove oligomers, residual monomers, generated gas and the like in the resin.

  The mixed resin composition of a polyacetal resin and a polymer having an aliphatic ester structure is not limited to a simple blend of a polymer having an aliphatic ester structure and a polymer having an oxymethylene structure. The copolymer etc. which are produced | generated by transesterification etc. in a molten state below are also contained. Moreover, the manufacturing method which adds the polymer which has an aliphatic ester structure in the stabilization process of the polymer which has an oxymethylene structure gives a uniform resin composition.

  The compound having reactivity with the carboxyl group used in the method for producing a resin molded body of the present invention is not particularly limited as long as it is a compound capable of blocking the carboxyl end group of the resin composition, and is not limited to PLA or polyacetal resin. Carboxyl groups such as lactic acid and formic acid produced by thermal decomposition or hydrolysis can also be blocked.

  As the compound having reactivity with the carboxyl group, at least one compound selected from oxazoline compounds, carbodiimide compounds, epoxy compounds and amide compounds can be used.

Examples of the oxazoline compound that can be used as a reactive compound with a carboxyl group used in the present invention include 2-vinyl-2-oxazoline, 5-methyl-2-vinyl-2-oxazoline, and 4,4-dimethyl-2. -Vinyl-2-oxazoline, 4,4-dimethyl-2-vinyl-5,5-dihydro-4H-1,3-oxazine, 4,4,6-trimethyl-2-vinyl-5,6-dihydro-4H 1,3-oxazine, 2-isopropenyl-2-oxazoline, styrene-2-isopropenyl-2-oxazoline, vinyloxazolines such as 4,4-dimethyl-2-isopropenyl-2-oxazoline, 1,3- Phenylenebis (2-oxazoline), 1,4-phenylenebis (2-oxazoline), 2,2-bis (2-oxazoline), 2,2 Bis (4-methyl-2-oxazoline), 2,2-bis (4,4-dimethyl-2-oxazoline), 2,2-bis (4-ethyl-2-oxazoline), 2,2-bis (4 , 4-Diethyl-2-oxazoline), 2,2-bis (4-propyl-2-oxazoline), 2,2-bis (4-butyl-2-oxazoline), 2,2-bis (4-hexyl-) 2-oxazoline), 2,2-bis (4-phenyl-2-oxazoline), 2,2-bis (4-cyclohexyl-2-oxazoline), 2,2-bis (4-
Benzyl-2-oxazoline), 2,2-ethylenebis (2-oxazoline), 2,2-tetramethylenebis (2-oxazoline), 2,2-hexamethylenebis (2-oxazoline), 2,2-octa Methylene bis (2-oxazoline), 2,2-ethylene bis (4-ethyl-2-oxazoline), 2,2-tetraethylene bis (4-ethyl-2-oxazoline), 2,2-cyclohexylene bis (4 Bisoxazoline compounds such as -ethyl-2-oxazoline), preferably styrene-2-isopropenyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 1,3-phenylenebis (2-oxazoline) However, it is not limited to these.

  Examples of the carbodiimide compound that can be used as a reactive compound with a carboxyl group used in the present invention include at least one carbodiimide group in the molecule, and are synthesized by a generally well-known method. For example, dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide, N , N′-di-2,6-diisopropylphenylcarbodiimide, 2,6,2 ′, 6′-tetraisopropyldiphenylcarbodiimide, and the like, but are not particularly limited thereto. Yes.

  As an epoxy compound that can be used as a reactive compound with a carboxyl group used in the present invention, a glycidyl ether compound, a glycidyl ester compound, a glycidyl amine compound, a glycidyl imide compound, and an alicyclic epoxy compound can be preferably used. More preferably used epoxy compounds include glycidyl ether compounds and glycidyl ester compounds. Specifically, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, triethylolpropane polyglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, sorbitol polyglycidyl ether, bisphenol A-di Examples thereof include, but are not limited to, glycidyl ether, hydrogenated bisphenol A-glycidyl ether, 4,4′-diphenylmethane diglycidyl ether, terephthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, and the like.

  Examples of the amide compound that can be used as a reactive compound with a carboxyl group used in the present invention include PA6 / 12 copolymer, PA66 / 12 copolymer, PA6 / 66/610 copolymer, PA6 / 66/12 copolymer. One or more polyamides selected from the group consisting of polymers, PA6 / 66/610/12 copolymers and dimer acid polyamides can be suitably used.

As the reactive compound with the carboxyl group, one or more compounds can be arbitrarily selected and used. It is preferable that the compounding quantity of the reactive compound with a carboxyl group is 0.01-20 weight part with respect to a total of 100 weight part of the polymer component which has a polyacetal resin and an aliphatic ester structure, 0.05- More preferably, it is 10 parts by weight. Moreover, after melt-kneading with the polymer which has an aliphatic ester structure previously, it can mix | blend with a polyacetal resin.
Furthermore, in the present invention, it is preferable to add a reaction catalyst of a reactive compound with a polymer terminal or a carboxyl group of an acidic low molecular weight compound.

Next, the manufacturing method of the resin molding of this invention is demonstrated. The apparatus to be used is not particularly limited. For example, the apparatus can be constituted by a melt kneading apparatus, a gear pump, a die having a desired shape, and a fish is removed by installing a filter on a breaker plate during melt kneading. To do.
Such fish eyes are defined as foreign substances formed by molding a resin obtained by the production method of the present invention into a film and visually observing the film. As the shape of the fish eye, various shapes such as a round shape and an elliptical shape are observed. The size of the fish eye was defined by the length of the long axis in cases other than the round shape.

  Examples of the filter include a wire mesh and a sintered filter. The wire mesh may be any of plain weave, twill weave, plain tatami weave, crimp net, welded wire mesh, turtle shell wire mesh, and the like. Sintered filters are made by integrating multiple layers of metal meshes, such as stainless steel, by sintering. Nonwoven fabric filters obtained by sintering felt from metal fibers, metals, ceramics, plastics, etc. Any powder or the like in which the powder is directly bonded to each other by heat and pressure may be used. This sintered filter does not have one kind of hole in a plane such as a wire mesh, but is a three-dimensional structure filter having various hole diameters in which pressed metal fibers are intertwined. Further, a disk type filter, a tube type filter, a flat type cylindrical filter, or a pleated type cylindrical filter obtained by processing these filter media may be used.

In order to achieve a low fisheye number level, a sintered filter having an absolute filtration accuracy of 50 μm or less, preferably 10 μm or less is advantageous, but if it is 500 mesh or more, preferably 700 mesh or more, a flat wire mesh is used. Screen packs consisting of filters can be used as well.
Here, the screen pack is used as a name of a constituent filter in which a plurality of filters are overlapped. Moreover, since the absolute filtration accuracy is defined as “the minimum glass bead diameter that can be supplemented by 95% or more by the filter medium”, the lower the numerical value, the higher the accuracy.
The manufacturing method of the resin molding of this invention is not specifically limited. For example, when manufacturing a fiber, it can manufacture by well-known methods, such as a melt blow method and a melt spinning method. Moreover, when manufacturing a film, it can manufacture by well-known methods, such as a T-die method or an inflation method.
The extrusion temperature at the time of production is not particularly limited, and is usually equal to or higher than the temperature at which either or either the polyacetal resin used as a raw material and the polymer having an aliphatic ester structure melt, specifically, the raw material resin. It is preferable to carry out at or above the flow start temperature.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention does not receive a restriction | limiting at all to a following example.
In addition, the evaluation test shown in the Example was done with the following method.

[Fish eye measurement]
The resin obtained by the production method of the present invention was formed into a film having a thickness of 30 μm using a T-die, and fish eyes having a major axis length of 30 μm or more contained in a 5 cm square were visually confirmed.

[Evaluation of spinnability]
Using a spinning device composed of a melt-kneading device with a cylinder set temperature of 200 ° C, a gear pump, and a discharge nozzle (0.8 mm diameter, 120 holes), the discharge rate is fixed at 3 kg / h, and the yarn is wound directly under the nozzle. The number of rotations at the time of cutting was recorded, and this was determined as follows as an index of spinnability. When the maximum winding speed was 300 m / min or more, ◎, when 100 m / min or more and less than 300 m / min, ○, and when 100 m / min or less, ×.

[Examples 1-3, Comparative Examples 1-3]
A quasi-triangular plate having a pair of shafts in a long case having an inner cross section in which two circles partially overlap each other, a long diameter of the inner cross section being 20 cm, and having a jacket around it, and each shaft meshing with each other Two continuous mixers that can clean the inner surface of the case and the surface of the counterpart pseudo-triangle plate at the tip of the pseudo-triangle plate are used as polymerization equipment, and the shaft is screw-like instead of a pseudo-triangle plate that meshes with each other. Oxymethylene copolymer with a structure in which a number of blades are fitted, a stopper mixer that injects a stopper solution from the supply port and continuously mixes with the polymer is connected in series The manufacture of was carried out.
At the inlet of the first stage polymerizer, 80 kg / hr (889 kmol / hr) of trioxane and 8 kg / hr (0.1 kmol / hr) of 1,3-dioxolane, and boron trifluoride diethyl etherate as a catalyst. Using a benzene solution, it was continuously fed so as to be 20 ppm as boron trifluoride with respect to the total amount of monomers. Further, methylal as a molecular weight regulator was continuously supplied in an amount necessary to adjust the intrinsic viscosity to 1.1 to 1.5 dl / g. The total amount of benzene used was 1% by weight or less based on trioxane. Further, from the inlet of the terminator mixer, triphenylphosphine having twice the molar amount of the catalyst used was continuously fed with a benzene solution to stop the polymerization, and a crude copolymer was obtained from the outlet. In the continuous polymerization machine, the rotation speed of each shaft is set to about 40 rpm, the first stage jacket temperature is set to 65 ° C., and the second stage and stop agent mixer jacket temperatures are set to 40 ° C. to perform the polymerization operation. It was. Further, triethylene glycol bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] (manufactured by Ciba Geigy, trade name Irganox 245) was added to 100 parts by weight of the obtained crude copolymer. ) After adding and mixing 0.3 parts by weight and 0.025 parts by weight of melamine, the same direction rotating twin screw extruder with a vent and a twin screw stirring blade type polymerizer were combined and heated and melted at 220 ° C. Then, it extracted with the gear pump and cooled in water and pelletized. The obtained pellets were dried with a hot air dryer at 120 ° C. for 24 hours to obtain a final sample. Polymers having an aliphatic ester structure are PLA: Terramac TE-2000 manufactured by Unitika Ltd., PEC: Upec PEC-350 manufactured by Mitsubishi Gas Chemical Co., Ltd., PBS: Bionore # 1001 manufactured by Showa Polymer Co., Ltd., PBSA: Showa High Bionore # 3001 manufactured by Molecular Corporation was used as it was.
As the reactive compound with the carboxyl group, a carbodiimide group-containing polymer (Nisshinbo Co., Ltd., Carbodilite LA-1) was used.
According to the composition shown in Table 1, each of the above materials was plasticized and melted by an extruder having a cylinder set temperature of 200 ° C., passed through various filters, and then subjected to an evaluation test. The results are shown in Table 1.

Claims (4)

  A melt of a polymer having a polyacetal resin and an aliphatic ester structure in which the number of fish eyes having a long axis length of 30 μm or more contained in a 5 cm square when formed into a film having a thickness of 30 μm is 5 or less Resin fiber obtained by spinning.   Polyacetal resin, polymer having aliphatic ester structure, and carboxyl group, wherein the number of fish eyes having a major axis length of 30 μm or more contained in a 5 cm square when formed into a film having a thickness of 30 μm is 5 or less Resin fiber obtained by spinning a melt of a compound having reactivity with.   The resin fiber according to claim 1 or 2, wherein the polymer having an aliphatic ester structure is polylactic acid, polyester carbonate, polybutylene succinate or polybutylene succinate adipate. The resin fiber according to claim 2 or 3, wherein the compound having reactivity with the carboxyl group is at least one compound selected from an oxazoline compound, a carbodiimide compound, an epoxy compound, and an amide compound.