JP2005306901A - Polyvinyl alcohol resin composition, melt molding product consisting of the same, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyvinyl alcohol type resin composition which is excellent in heat stability and can stably be molded by heat melting without problems of gellation or coloring. <P>SOLUTION: The polyvinyl alcohol type resin composition comprises 100 pts.wt. of a vinyl alcohol type polymer (A) and 0.01-10 pts.wt. of a fatty acid ester compound (B) whose total carbon atoms of the fatty acid unit is ≥36, wherein the content of an alkaline metal element to 100 pts.wt. of the vinyl alcohol type polymer (A) is 0.00001-0.05 pt.wt. The vinyl alcohol type polymer (A) is preferably a modified polyvinyl alcohol containing 1-20 mol% of a ≤4C α-olefin unit and preferably contains a plasticizer (C) in an amount of 1-30 pts.wt. based on 100 pts.wt. of the vinyl alcohol type polymer (A). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyvinyl alcohol resin composition comprising a vinyl alcohol polymer (hereinafter sometimes abbreviated as PVA) and a fatty acid ester compound, and a method for producing the same. The present invention also relates to a melt-molded product comprising the resin composition and a fiber obtained by melt spinning the resin composition.

  When PVA is heat-treated and thermoformed, thermal stability (coloring, odor, viscosity, etc.) is extremely important. In particular, regarding melt molding, PVA has a very close thermal melting start temperature and thermal decomposition temperature, and is much more degraded than polyethylene and polypropylene, and it is very difficult to continuously mold at high temperatures. there were. Moreover, since PVA has high adhesiveness with a metal, it has a problem of causing stagnation inside the metal pipe during molding and promoting deterioration. Therefore, in order to easily melt-mold PVA, a technique for lowering the melting point or improving the fluidity of PVA has been made by a method such as copolymerization of a comonomer or addition of a plasticizer or water. Furthermore, by adding a lubricant such as a metal soap, it has been devised to prevent the PVA from adhering to the metal in the piping of the molding machine and to improve the lubricity at the resin retaining portion.

  However, a lubricant such as a metal soap is mainly composed of a salt of a divalent metal such as magnesium or calcium, and has a problem that the strength of the molded product becomes insufficient as a result of promoting the decomposition reaction of PVA. Furthermore, since these lubricants have a high melting point, they are likely to be deposited during melt molding, causing die lines and blisters, making long-term continuous molding difficult. Further, during melt spinning, the nozzles become soiled, the yarn is broken frequently and stable spinning cannot be performed, and further improvement measures are required.

  In JP-A-6-271735 (Patent Document 1), a PVA containing an oxyalkylene group having an alkali metal salt content of 0.1% by weight or less and containing a certain amount of acid is specified. A resin composition to which a heat stabilizer is added is described. In the resin composition, it is said that thermal stability can be improved by adding a fatty acid derivative selected from fatty acids having 10 or more carbon atoms, salts thereof, amides and esters thereof. However, when the fatty acid derivatives exemplified in the specification of the publication and the fatty acid derivatives used in the examples are used, the thermal stability of the resin composition is still insufficient, and melt spinning is performed. In some cases, such as when high melt stability is required, it is difficult to use. This is considered to be because the effect as a lubricant which those fatty acid derivatives have is insufficient.

  Japanese Patent Application Laid-Open No. 2001-72710 (Patent Document 2) describes a method for producing modified PVA in which PVA and a carboxylic acid ester of a polyhydric alcohol are heated and reacted. Is possible. However, when the carboxylic acid ester specifically used in the examples of the publication is used, the thermal stability of the resin composition is still insufficient, and a high degree of melt stability is required. Was difficult to use. Moreover, the transesterification reaction between the carboxylic acid ester and the hydroxyl group of PVA easily progressed during melt kneading, and it was difficult for the carboxylic acid ester to act effectively as a lubricant.

  Japanese Patent Application Laid-Open No. 2001-302868 (Patent Document 3) describes a hot-melt PVA resin composition composed of PVA having a predetermined polymerization degree and an alkylene oxide adduct of a polyhydric alcohol. Also described is a method for producing a fiber by melt spinning a resin composition using ethylene-modified PVA. However, when high thermal stability is required, such as when melt spinning at a high temperature, the thermal stability is still insufficient.

JP-A-6-271735 (claims, columns 0016, 0017, examples) JP 2001-72710 A (Claims, Examples) JP 2001-302868 A (Claims)

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a polyvinyl alcohol-based resin composition excellent in thermal stability and suitable for hot melt molding and a method for producing the same. . Another object of the present invention is to provide a melt-molded product, particularly a fiber or film, which can be stably produced over a long period of time, comprising such a resin composition.

  The subject consists of 100 parts by weight of a vinyl alcohol polymer (A) and 0.01 to 10 parts by weight of a fatty acid ester compound (B) having a total carbon number of 36 or more, and the vinyl alcohol polymer (A). This is solved by providing a polyvinyl alcohol-based resin composition having an alkali metal element content of 0.00001 to 0.05 parts by weight with respect to 100 parts by weight.

  At this time, the vinyl alcohol polymer (A) preferably contains 1 to 20 mol% of an α-olefin unit having 4 or less carbon atoms, particularly an ethylene unit. It is also preferred that the fatty acid ester compound (B) is a completely ester-substituted product, particularly a fatty acid triester of glycerin. The plasticizer (C) is also preferably contained in an amount of 1 to 30 parts by weight with respect to 100 parts by weight of the vinyl alcohol polymer (A). In this case, the plasticizer (C) is trivalent or more polyvalent. A compound obtained by adding 1 to 30 moles of alkylene oxide to 1 mole of alcohol is preferable.

  A melt-molded product comprising the polyvinyl alcohol-based resin composition is a preferred embodiment. Further, a fiber obtained by melt spinning the polyvinyl alcohol resin composition, particularly a composite fiber, is a preferred embodiment.

  The above-mentioned subject is a fatty acid unit with respect to 100 weight part of vinyl alcohol polymer (A) whose content of alkali metal element is 0.00001-0.05 weight part to 100 weight part of vinyl alcohol polymer (A). It is also solved by providing a method for producing a polyvinyl alcohol-based resin composition in which 0.01 to 10 parts by weight of the fatty acid ester compound (B) having a total carbon number of 36 or more is blended. At this time, it is preferable to mix and knead the vinyl alcohol polymer (A) and the fatty acid ester compound (B).

  Since the polyvinyl alcohol-based resin composition of the present invention is excellent in thermal stability, gelation and coloring can be suppressed during hot melt molding. In particular, it has excellent processability when a fiber is produced by melt spinning for a long time, or when a film is produced by melt film formation for a long time.

  The present invention is described in detail below. The polyvinyl alcohol resin composition of the present invention comprises a vinyl alcohol polymer (A) and a fatty acid ester compound (B).

  PVA (A) is obtained by saponifying a polymer of vinyl ester. Examples of the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate and the like, but industrially vinyl acetate is often used.

  There is no restriction | limiting in particular in the polymerization degree and saponification degree of PVA (A). However, considering the mechanical strength and shape stability of the molded product obtained, and also the viscosity stability during molding, those having a degree of polymerization of 100 to 2000 are preferably used, those having 150 to 1500 are more preferable, and 200 Particularly preferred is ~ 1000. The degree of saponification is preferably 90 to 99.99 mol%, more preferably 95 to 99.98 mol%, considering thermal stability during molding. The degree of polymerization can be arbitrarily changed mainly by adjusting the polymerization rate and the amount of solvent. As for the degree of saponification, an arbitrary value can be obtained mainly by adjusting the catalyst concentration, reaction time, and reaction temperature.

  Furthermore, PVA (A) may contain an α-olefin unit. The α-olefin unit is preferably one having 4 or less carbon atoms, and examples thereof include ethylene, propylene, 1-butene, and isobutene, and ethylene is more preferable in consideration of water resistance and hygroscopicity. An α-olefin unit having 5 or more carbon atoms is not preferable because the water solubility of the produced PVA is lowered. In the case of a β-olefin unit, it is difficult to use in the present invention from the viewpoint of polymerization reactivity. The preferable content of the α-olefin unit is 1 to 20 mol%. When the content exceeds 20 mol%, the performance of water solubility, which is the most important requirement of PVA, is impaired, and the modified PVA Solubility in water decreases.

  PVA (A) may contain monomer units other than vinyl alcohol units, vinyl ester units, and α-olefin units as long as the effects of the present invention are not impaired. Such units include unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, (anhydrous) phthalic acid, (anhydrous) maleic acid, (anhydrous) itaconic acid, and salts thereof, or alkyls having 1 to 18 carbon atoms. Esters; acrylamides such as acrylamide, N-alkyl acrylamide having 1 to 18 carbon atoms, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid and its salt, acrylamidepropyldimethylamine and its acid salt or quaternary salt thereof Methacrylamide, C1-C18 N-alkylmethacrylamide, N, N-dimethylmethacrylamide, 2-methacrylamidepropanesulfonic acid and its salt, methacrylamidepropyldimethylamine and its acid salt or its quaternary salt, etc. Methacrylamides N-vinylamides such as N-vinylpyrrolidone, N-vinylformamide and N-vinylacetamide; vinyl cyanides such as acrylonitrile and methacrylonitrile; methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n -Vinyl ethers such as butyl vinyl ether; allyl acetate; allyl ethers such as propyl allyl ether, butyl allyl ether, and hexyl allyl ether; vinyl halides such as vinyl chloride, vinyl fluoride, and vinyl bromide; vinylidene chloride, fluoride Vinylidene halides such as vinylidene; vinylsilanes such as trimethoxyvinylsilane; monomers having an oxyalkylene group such as polyoxyalkylene allyl ether; Penyl; 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, 7-octen-1-ol, 9-decene-1-ol, 3-methyl-3-butene- Hydroxyl group-containing α-olefins such as 1-ol; monomers having a carboxyl group derived from fumaric acid, maleic acid, itaconic acid, maleic anhydride, phthalic anhydride, trimellitic anhydride, etc .; ethylene sulfonic acid , Monomers having a sulfonic acid group derived from allylsulfonic acid, methallylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, etc .; vinyloxyethyltrimethylammonium chloride, vinyloxybutyltrimethylammonium chloride, vinyloxyethyl Dimethylamine, vinyloxymethyldiethylamine, N-acrylamide Examples include monomers having a cationic group derived from til trimethylammonium chloride, N-acrylamidoethyltrimethylammonium chloride, N-acrylamidodimethylamine, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, dimethylallylamine, allylethylamine, and the like. .

  Among these monomers, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl, from the viewpoint of availability, copolymerizability and melt moldability of the resulting copolymer. Vinyl ethers such as vinyl ether; allyl acetate; allyl ethers such as propyl allyl ether, butyl allyl ether and hexyl allyl ether; monomers having an oxyalkylene group such as polyoxyalkylene allyl ether; 3-buten-1-ol; Hydroxyl-containing α such as 4-penten-1-ol, 5-hexen-1-ol, 7-octen-1-ol, 9-decen-1-ol, 3-methyl-3-buten-1-ol -Olefins are preferred.

  The content (copolymerization ratio) of these monomers is usually 20 mol% or less, preferably 10 mol% or less, more preferably 5 mol% or less.

  Examples of the polymerization method of the vinyl ester polymer include known methods such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method. Among them, a bulk polymerization method or a solution polymerization method in which polymerization is performed without solvent or in a solvent such as alcohol is usually employed. Examples of alcohol used as a solvent during solution polymerization include lower alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol. Examples of the initiator used for the polymerization include α, α′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile, benzoyl peroxide, n-propyl peroxycarbonate, etc. And known initiators such as azo initiators and peroxide initiators.

  The vinyl ester polymer is saponified by a known method. For example, it is saponified in a state dissolved in alcohol. Examples of the alcohol used for the saponification reaction include lower alcohols such as methyl alcohol and ethyl alcohol, and methyl alcohol is particularly preferably used. In particular, the polymerization of the vinyl ester and the saponification reaction of the obtained vinyl ester polymer are preferably performed using the same solvent. In this respect, methanol is preferably used as the solvent. The alcohol used for the saponification reaction may contain a solvent such as acetone, methyl acetate, ethyl acetate, and benzene as long as it is 40% by weight or less. As a catalyst used for the saponification reaction, an alkali metal hydroxide such as potassium hydroxide or sodium hydroxide, an alkali catalyst such as sodium methylate, or an acid catalyst such as mineral acid is used. Although there is no restriction | limiting in particular about the temperature of saponification reaction, The range of 20-60 degreeC is suitable. When the product precipitates with the progress of the saponification reaction, the product is pulverized at that point, washed and then dried to obtain PVA (A).

  The polyvinyl alcohol-based resin composition of the present invention contains 0.00001 to 0.05 parts by weight of an alkali metal element with respect to 100 parts by weight of PVA (A). Examples of the alkali metal element include potassium, sodium, and the like, which are mainly salts of lower fatty acids such as acetic acid and propionic acid, or carboxyl groups and sulfonic acid groups contained in the monomer unit of PVA (A). Exists as a salt. The content of the alkali metal element with respect to 100 parts by weight of PVA (A) is preferably 0.00003 to 0.03 parts by weight, and more preferably 0.00005 to 0.01 parts by weight. Those having an alkali metal element content of less than 0.00001 parts by weight are difficult to produce industrially. Furthermore, the obtained resin does not exhibit sufficient water solubility, and undissolved substances may remain. On the other hand, when the content of the alkali metal element exceeds 0.05 parts by weight, decomposition and gelation at the time of melt molding may be severe and molding may be difficult, and coloring of the resulting molded product or film is also remarkable. The content of the alkali metal element in the general-purpose PVA is usually in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of PVA. Therefore, the content of the alkali metal element in the PVA (A) used in the present invention is much smaller than that of the general-purpose PVA.

  The method for incorporating a specific amount of alkali metal element in the resin composition of the present invention is not particularly limited. Since the fatty acid ester compound (B) and the plasticizer (C) usually do not contain an alkali metal element, the alkali metal element in the resin composition is preferably contained in the raw material PVA (A). . As a method of adjusting the alkali metal element content of PVA (A), a method of adding a compound containing an alkali metal once PVA is obtained, and a saponification in producing a PVA by saponifying a vinyl ester polymer, A method of controlling the amount of the alkali metal element contained in the PVA by using an alkaline substance containing an alkali metal as a catalyst and washing the saponified PVA with a washing liquid is mentioned. It is preferable as a method. The content of the alkali metal element in PVA (A) can be determined by atomic absorption analysis.

  Furthermore, in the resin composition of the present invention, it is important to contain a specific amount of a fatty acid ester compound (B) having a total number of carbon atoms of fatty acid units of 36 or more. Here, the total carbon number of the fatty acid unit is a total value of the carbon number contained in one or more fatty acid residues constituting the fatty acid ester compound (B). When the number of carbon atoms is less than 36, compatibility is not a problem, but sufficient external lubricity is not imparted because both the molecular weight and hydrophobicity are low.

  The fatty acid ester compound (B) used in the present invention has a fatty acid unit having a total carbon number of 36 or more. Specific examples thereof include ethylene glycol distearate, ethylene glycol dibehenylate, glycerin trilaurate, glycerin distearate, glycerin tristearate, glycerin dibehenylate, glycerin tribehenylate, pentaerythritol trilaurate, Higher polyhydric alcohols such as pentaerythritol tetralaurate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate, pentaerythritol dibehenylate, pentaerythritol tribehenylate, pentaerythritol tetrabehenylate Examples include fatty acid esters, among which ethylene glycol distearate, ethylene glycol dibehenylate, glycerin It is preferably a complete ester substitution product such as laurate, glycerin tristearate, glycerin tribehenylate, pentaerythritol tetralaurate, pentaerythritol tetrastearate, pentaerythritol tetrabehenylate, etc. Glycerol triesters such as stearate and glycerin tribehenylate are more preferred. As the fatty acid constituting the fatty acid ester compound (B), a higher fatty acid having 12 or more carbon atoms is preferable. Moreover, as a polyhydric alcohol, C2-C5 alcohols, such as ethylene glycol, glycerol, a pentaerythritol, are preferable. Of course, in this invention, you may use together 2 or more types of fatty acid ester compounds (B) as a fatty acid ester compound (B).

  In the resin composition of the present invention, the blending ratio of the fatty acid ester compound (B) to 100 parts by weight of PVA (A) is 0.01 to 10 parts by weight, preferably 0.01 to 8 parts by weight, 7 parts by weight is more preferable, and 0.03 to 5 parts by weight is particularly preferable. When the blending ratio of the fatty acid ester compound (B) is less than 0.01 parts by weight, the lubricity during molding is insufficient, and when the blending ratio of the fatty acid ester compound (B) exceeds 10 parts by weight. This is not preferable because the strength of the molded product is reduced, hardness, stiffness, and shape stability are lacking, and problems such as blocking properties occur.

  It is preferable that the resin composition of the present invention further contains a plasticizer (C) because the molding temperature can be lowered and the fluidity during molding can be improved. Examples of the plasticizer (C) include polyhydric alcohols such as glycerin, diglycerin and diethylene glycol, alkylene oxide adducts of these polyhydric alcohols, polyethers such as polyethylene glycol and polypropylene glycol, and phenols such as bisphenol A and bisphenol S. Examples include derivatives, amide compounds such as N-methylpyrrolidone, water, and the like.

  Among these plasticizers (C), it is excellent in thermal stability to add a compound obtained by adding 1 to 30 mol of alkylene oxide, particularly preferably ethylene oxide to 1 mol of a trihydric or higher polyhydric alcohol, It is preferable from the viewpoint of excellent compatibility with PVA. When the average number of added moles of alkylene oxide is less than 1, the compatibility is not a problem, but the plasticizing effect is lowered because the molecular weight is low. Moreover, since the SP value will fall when the average addition mole number of alkylene oxide exceeds 30, compatibility with PVA will fall. The number of added moles is an average, and there may be a distribution in the number of added moles, but it is not preferable that more than 30 moles of adduct are mixed in at 50% by weight or more. More preferred is a compound to which 1 to 10 mol% of ethylene oxide has been added, and further preferred is a compound to which 1 to 4 mol% of ethylene oxide has been added. Preferred examples of the polyhydric alcohol used as the plasticizer (C) and constituting the alkylene oxide adduct of the polyhydric alcohol include C3-C6 trihydric alcohols such as glycerin, pentaerythritol, and sorbitol. It is done. Moreover, it is preferable that the average molecular weights of a plasticizer (C) are 200-1500.

  The resin composition of the present invention preferably contains 1 to 30 parts by weight of the plasticizer (C), more preferably 2 to 20 parts by weight.

  In the resin composition of the present invention, in addition to the fatty acid ester compound (B), in some cases, what is generally used as a PVA lubricant is mixed and used within a range not losing the characteristics of the present invention. You can also These lubricants include lauric acid amide, oleic acid amide, stearic acid amide, palmitic acid amide, behemic acid amide, lauric acid amide EO adduct, stearic acid amide EO adduct, behemic acid amide EO adduct, ethylenebislauryl. Fatty acid amide compounds such as acid amide, ethylene bis stearic acid amide, ethylene bis behemic acid amide, methylene bis stearic acid amide, hydrocarbon compounds such as liquid paraffin and polyethylene wax, butyl stearate, rice wax, hydrogenated castor oil Alcohol esters of fatty acids such as ethylene glycol monostearate, fatty acid polyhydric alcohol esters, fatty acid polyglycol ester compounds, alcohol compounds such as cetyl alcohol and stearyl alcohol Murrell. At this time, when using a fatty acid ester as a lubricant other than the fatty acid ester compound (B), the total number of carbon atoms in the fatty acid unit is less than 36. The addition amount of these lubricants is preferably 0.01 to 1 part by weight with respect to 100 parts by weight of PVA (A).

  The resin composition of the present invention may contain ordinary additives such as fillers, colorants, fibers such as glass fibers and carbon fibers, fragrances, foaming agents, extenders, release agents, and UV absorbers as necessary. It may be blended appropriately. For example, as a filler, inorganic powder can be added as a form stability, blocking prevention, or hardness imparting agent. For example, talc, calcium carbonate, clay, mica, titanium oxide, etc., and the average particle size is preferably 0.2 to 10 μm. Further, the addition amount is preferably 0 to 100 parts by weight with respect to 100 parts by weight of PVA (A).

  As a method for producing the resin composition of the present invention, a method in which PVA (A) and a fatty acid ester compound (B), in some cases, a plasticizer (C) are blended in advance, and then melt-kneaded and pelletized, a melt-kneader Kneading and pelletizing while charging separately at a fixed ratio, and further, charging and kneading each into an extruder for direct molding, and extruding the kneaded product into a fiber or film shape to obtain a molded product, etc. Can be mentioned.

  The melt molding method using the resin composition of the present invention is not particularly limited, and is an extrusion molding method such as a T-die extrusion method, an inflation molding method, a direct blow molding method, a hollow molding method, an injection molding method, or a compression molding method. Any molding method including melt spinning can be used. It may be co-extruded with another resin, or may be laminated by melt extrusion on another material such as paper or film.

  The resin composition comprising the modified PVA (A) and the fatty acid ester compound (B) of the present invention, and optionally a plasticizer (C), is not only molded alone, but also polyethylene, polypropylene, ABS resin, polystyrene, polyester, It can be blended with other general-purpose resins such as polyamide, laminated, and mixed and spun. The molded product thus obtained can improve the hydrophilicity of the hydrophobic resin and improve the wettability with respect to water. Further, after molding, the PVA resin part is dissolved and removed with water to remove a hollow molded product or a porous molded product. In addition, a fine molded product can be obtained. For example, a bundle of hollow fibers or ultrafine fibers can be obtained.

  As an example, in the production of fibers using the resin composition of the present invention, a known melt spinning apparatus can be used. That is, it is obtained by melting the resin composition pellets of the present invention with a melt extruder, guiding the molten polymer to the spinning head, measuring it with a gear pump, and winding the yarn discharged from the nozzle.

  The yarn discharged from the spinning nozzle is wound at a high speed without being stretched, or is stretched as necessary. Stretching may be performed after winding and then stretching after being discharged from the spinning nozzle, or may be performed subsequent to stretching, and any may be used in the present invention. The obtained yarn is cut as necessary and used in a monofilament or multifilament state without being cut, or in the form of a woven fabric, a knitted fabric, a nonwoven fabric or a laminate thereof. PVA may be removed in a process of treating with hot water such as a dyeing process.

  In particular, it is preferable to produce a composite fiber by performing so-called composite spinning, in which the resin composition of the present invention and a thermoplastic resin other than PVA are combined immediately before the spinneret and extruded and spun in that state. When manufacturing such a composite fiber, the shape of the spinning pack is complicated, so that the molten resin is likely to stay, and the spinning is often performed at a high temperature in accordance with the melting point of a thermoplastic resin other than PVA. Therefore, a high thermal melting stability is required for the PVA resin composition. Therefore, it is particularly preferable to use the resin composition of the present invention having excellent thermal stability. Although it does not specifically limit as thermoplastic resins other than PVA, Polyester, polyolefin, and polyamide are mentioned as a suitable thing, Especially polyester with high melting | fusing point is suitable.

  The resin composition of the present invention can be stably melt-molded without problems such as gelation, and various melt-molded products such as fibers, nonwoven fabrics, films, and other molded products are obtained from the resin composition of the present invention. be able to. As an example, by mixing or combining with other polymers to form a fiber or film, the PVA resin composition is removed from the resulting molded product such as fiber or film to obtain a porous fiber, porous film, or ultrafine fiber. Etc., and is used as clothing and various packaging materials as ultrafine fibers as a fiber or film excellent in heat retention and anti-transparency.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited by this. In the following examples and comparative examples, “parts” and “%” mean weight basis unless otherwise specified. The degree of polymerization and the degree of saponification were measured according to JIS K6726. The amount of α-olefin modification in PVA was determined by NMR measurement. Furthermore, the content of the alkali metal element was measured with an atomic absorption photometer using the one dissolved in acid after ashing the modified PVA.

  Furthermore, the hue, film forming processability, and fiberizing processability described in the examples were measured and evaluated by the following methods and standards.

[Hue]
The hue value of the lubricant-added pellet was measured with a Spectro Color Meter (color difference meter).

[Film processability]
The film forming temperature was 230 ° C., and the film was formed into a film having a thickness of 40 μm by adjusting the take-off speed at a discharge rate of 1.5 kg / h during the forming. Film formation was carried out continuously for 24 hours, and the number of bumps (thickness of 1 mm or more) in the film (size: 20 × 20 cm) after 24 hours was measured.

[Fiberification process properties]
PVA and polyester are melted and kneaded with separate extruders, and PVA is placed on the sheath side, and polyester is placed on the core side at 230 ° C or 270 ° C, and the core-sheath ratio is 1: 1. Fiber was obtained. The spinning condition at this time was evaluated.
A: It can be wound up for 5 hours without any single yarn breakage.
B: Although there is one single yarn breakage in 5 hours, it can be wound up as a multifilament for 5 hours.
C: Single yarn breakage occurs twice or more in 5 hours, but can be wound up as a multifilament for 5 hours.
D: Single yarn breakage is remarkable and can be wound up as a multifilament only for about 30 minutes.
E: Single yarn breakage is remarkable and can be wound only as a multifilament for about 5 minutes.
F: Single yarn breakage is remarkable and cannot be wound at all.

Example 1
[Production of ethylene-modified PVA]
A 100 L pressure reactor equipped with a stirrer, nitrogen inlet, ethylene inlet, initiator addition port and delay solution addition port was charged with 29.0 kg of vinyl acetate and 31.0 kg of methanol, heated to 60 ° C. and then 30 The system was purged with nitrogen by nitrogen bubbling for 1 minute. Next, ethylene was introduced and charged so that the reactor pressure was 5.9 kg / cm ² . Prepare a 2.8 g / L solution of 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMV) dissolved in methanol as an initiator, and perform nitrogen substitution by bubbling with nitrogen gas. did. After adjusting said polymerization tank internal temperature to 60 degreeC, 170 mL of said initiator solutions were inject | poured and polymerization was started. During the polymerization, ethylene was introduced to maintain the reactor pressure at 5.9 kg / cm ² , the polymerization temperature at 60 ° C., and polymerization was carried out by continuously adding AMV at 610 mL / hr using the above initiator solution. did. After 10 hours, when the polymerization rate reached 70%, the polymerization was stopped by cooling. After the reaction vessel was opened to remove ethylene, nitrogen gas was bubbled to completely remove ethylene. Next, unreacted vinyl acetate monomer was removed under reduced pressure to obtain a methanol solution of polyvinyl acetate. Methanol was added to the obtained polyvinyl acetate solution to adjust the concentration to 50%, and 46.5 g (polyvinyl acetate) was added to 200 g of the polyvinyl acetate methanol solution (100 g of polyvinyl acetate in the solution). Saponification was carried out by adding an alkaline solution (NaOH in 10% methanol) having a molar ratio (MR) of 0.10 to the vinyl acetate unit therein. About 2 minutes after the addition of the alkali, the gelled system was pulverized by a pulverizer, allowed to stand at 60 ° C. for 1 hour to proceed with saponification, and then 1000 g of methyl acetate was added to neutralize the remaining alkali. After confirming the end of neutralization using a phenolphthalein indicator, 1000 g of methanol was added to a white solid PVA resin obtained by filtration and washed at room temperature for 3 hours. After the above washing operation was repeated three times, the PVA resin obtained by centrifugal drainage was left to dry in a dryer at 70 ° C. for 2 days to obtain ethylene-modified PVA (A).

  When the obtained PVA (A) was analyzed according to JIS K6726, the degree of polymerization was 330, the degree of saponification was 98.4 mol%, and the amount of ethylene modification was 10 mol%. Moreover, content of the alkali metal element was 0.0002 weight part with respect to PVA (A). 0.1 parts by weight of glycerin tristearate (total number of carbon atoms of fatty acid unit: 54) as a fatty acid ester compound (B) is added to 100 parts by weight of the powder of PVA (A), and sorbitol as a plasticizer (C). 8 parts by weight of an ethylene oxide 2-mole adduct (SE-270 manufactured by Sanyo Chemical Co., Ltd.) was kneaded while being charged at a constant rate, and extruded under the following conditions to produce pellets.

(Pelletization conditions)
Extruder: Labo plast mill manufactured by Toyo Seiki Co., Ltd. Screw: 2-axis same direction, 25 mmφ, L / D = 26
Screw rotation speed: 60rpm
Set temperature: 220 ° C
Discharge rate: 3.2 kg / h

Next, pellets were supplied to an extruder equipped with a T die to form a film.
(Filming conditions)
Molding machine: Toyo Seiki Co., Ltd., Labo Plast Mill (single axis 25mmφ L / D = 28, rotation speed 20rpm)
T die: Effective width 300mm
Lip clearance: 0.2mm
Motor: 200V rating 20A

The pellets were supplied to the extruder and melt-spun.
(Fiberification conditions)
Composite ratio: PVA (A) / polyester = 50/50
Discharge amount: 29.2 g / min Nozzle: core-sheath type, 0.24 mmφ × 24 holes Spinning head temperature: 230 ° C., 270 ° C.
Spinning speed: 4000m / min

  Table 1 shows the hue of the pellet, the film forming processability, and the fiberizing processability. A good film with little coloring and no defects was obtained. Even during fiberization, no single yarn breakage occurred and stable processability was exhibited.

Examples 2 and 3
As shown in Table 1, pelletizing, film forming, and fiberizing tests were performed in the same manner as in Example 1 except that the addition amount of glycerin tristearate was changed. The evaluation results are shown in Table 1. Film formation with less fluffing was possible and spinnability was also good.

Comparative Example 1
In Example 1, pelletizing, film forming, and fiberizing tests were performed in the same manner as in Example 1 except that the fatty acid ester compound (B) and the plasticizer (C) were not blended at all. The results are shown in Table 1. In the film formation, the generation of fuzz was intense, and in the fiberization process, frequent yarn breakage and continuous spinning were impossible.

Comparative Examples 2 and 3
Except changing the addition amount of the fatty acid ester compound (B) of Example 1, the pelletization, the film formation, and the fiberization test were conducted in the same manner as in Example 1. The results are shown in Table 1. In Comparative Example 2, since the amount of the fatty acid ester compound (B) was small, the expected slipperiness could not be sufficiently imparted, and there were many problems in film formation. In the fiberization test, stable spinning could not be performed. In Comparative Example 3, there was no problem in film formation and spinnability, but the obtained film was severely blocked. In addition, a low-strength fiber was obtained, which was impractical.

Examples 4 and 5
Pelletization, film forming, and fiberization test were performed in the same manner as in Example 1 except that PVA (A) shown in Table 1 was used instead of PVA (A) used in Example 1. The evaluation test results are shown in Table 1. There was no problem in film formability and spinnability. In addition, content of the alkali metal element of PVA (A) used in Example 4 and 5 was 0.003 and 0.02 weight part with respect to 100 weight part of PVA (A), respectively.

Comparative Example 4
Pelletization, film forming, and fiberization test were performed in the same manner as in Example 1 except that PVA shown in Table 1 was used instead of PVA (A) used in Example 1. The evaluation test results are shown in Table 1. In film forming, the occurrence of bumps was a problem. In the fiberization test, stable spinning could not be performed. In addition, content of the alkali metal element of PVA used was 0.09 weight part with respect to 100 weight part of PVA (A).

Examples 6-11
Pelletization, film forming, and fiberization test were performed in the same manner as in Example 1 except that the fatty acid ester compound (B) shown in Table 1 was used instead of the fatty acid ester compound (B) used in Example 1. . Coloring, film moldability, and fiberizing process properties are shown in Table 1. In any of the examples, a film with less fluff was obtained and the spinnability was also good.

Example 12
Except that the plasticizer (C) of Example 1 was not blended at all, pelletization, film forming, and fiberizing test were performed in the same manner as in Example 1. The results are shown in Table 1. There was no problem in film formability and spinnability.

Example 13
Pelletization, film forming, and fiberization test were performed in the same manner as in Example 1 except that diglycerin was used instead of the plasticizer (C) used in Example 1. The evaluation test results are shown in Table 1. There was no problem in film formability and spinnability.

Examples 14 and 15
Pelletization, film molding, and fiberization test were performed in the same manner as in Example 1 except that PVA (A) shown in Table 1 was used instead of PVA (A) used in Example 1. Coloring, film moldability, and fiberizing process properties are shown in Table 1. There was no problem in film formability and spinnability.

Comparative Examples 5-8
Pelletization, film molding, and fiberization tests were performed in the same manner as in Example 1 except that the compounds shown in Table 1 were used instead of the fatty acid ester compound (B) used in Example 1. Coloring, film moldability, and fiberizing process properties are shown in Table 1. There were many bumps in film forming. Even in the fiberization test, many yarn breaks occurred.

  As described above, in Examples 1 to 15, long-time melt film formation and melt spinning can be performed without any problem, and are preferably Example 1, Examples 6 to 8, and Example 10, and more preferably Example 1. 6 was good. On the other hand, in Comparative Examples 1-8, melt molding could not be performed stably, and problems were caused in terms of processability and physical properties of the obtained molded product.

Claims (12)

It consists of 100 to 10 parts by weight of a vinyl alcohol polymer (A) and 0.01 to 10 parts by weight of a fatty acid ester compound (B) having a total carbon number of 36 or more, and is based on 100 parts by weight of the vinyl alcohol polymer (A). A polyvinyl alcohol-based resin composition having an alkali metal element content of 0.00001 to 0.05 parts by weight. The polyvinyl alcohol resin composition according to claim 1, wherein the vinyl alcohol polymer (A) is a modified polyvinyl alcohol containing 1 to 20 mol% of an α-olefin unit having 4 or less carbon atoms. The polyvinyl alcohol resin composition according to claim 2, wherein the α-olefin unit having 4 or less carbon atoms is an ethylene unit. The polyvinyl alcohol resin composition according to any one of claims 1 to 3, wherein the fatty acid ester compound (B) is a completely ester-substituted product. The polyvinyl alcohol-based resin composition according to claim 4, wherein the fatty acid ester compound (B) is a fatty acid triester of glycerin. The polyvinyl alcohol-type resin composition in any one of Claims 1-5 which contain 1-30 weight part of plasticizers (C) with respect to 100 weight part of vinyl alcohol-type polymers (A). The polyvinyl alcohol resin composition according to claim 6, wherein the plasticizer (C) is a compound obtained by adding 1 to 30 moles of alkylene oxide to 1 mole of a trihydric or higher polyhydric alcohol. A melt-molded product comprising the polyvinyl alcohol-based resin composition according to any one of claims 1 to 7. The fiber formed by melt-spinning the polyvinyl alcohol-type resin composition in any one of Claims 1-7. The fiber according to claim 9, which is a composite fiber. The total number of carbon atoms in the fatty acid unit with respect to 100 parts by weight of the vinyl alcohol polymer (A) having an alkali metal element content of 0.00001 to 0.05 parts by weight with respect to 100 parts by weight of the vinyl alcohol polymer (A). The manufacturing method of the polyvinyl-alcohol-type resin composition which mix | blends 0.01-10 weight part of fatty acid ester compounds (B) 36 or more. The method for producing a polyvinyl alcohol resin composition according to claim 11, wherein the vinyl alcohol polymer (A) and the fatty acid ester compound (B) are blended and melt-kneaded.