JP6161531B2 - Molded product and manufacturing method thereof - Google Patents

Description

  The present invention relates to a molded article obtained by melt-molding a polyvinyl alcohol-based resin composition and a method for producing the same. More specifically, the present invention is excellent in melt moldability and exhibits active energy rays such as EB (electron beam) and ultraviolet rays. The present invention relates to a molded article capable of improving water resistance by irradiation and a method for producing the same.

  Conventionally, a polyvinyl alcohol (hereinafter also referred to as “PVA”) resin is used as a water-soluble resin in various applications. However, since the PVA resin usually has a melting point and a decomposition point close to each other, it is substantially impossible to perform melt molding, and the restriction has been a major obstacle to further application development of the PVA resin.

On the other hand, in recent years, as a PVA resin that can be melt-molded, a PVA resin having a 1,2-diol structural unit in the side chain (hereinafter also referred to as a 1,2-diol PVA resin) is, for example, a patent. It is disclosed in Document 1.
However, 1,2-diol PVA-based resins are more hydrophilic than general PVA-based resins and have excellent water solubility, making it difficult to resist water and cannot be used for applications that require water resistance. there were.

On the other hand, an acetoacetyl group-containing PVA-based resin (hereinafter also referred to as AA-PVA-based resin) is an example of a PVA that is excellent in reactivity and can be crosslinked with a crosslinking agent to obtain a crosslinked polymer having excellent water resistance. It is disclosed in Document 2.
However, AA-PVA resins, like general PVA resins, are difficult to melt-mold and have been considered to be inapplicable to melt-molded products.

JP 2004-075866 A JP 2010-77385 A

  An object of this invention is to provide the molded product which is excellent in melt moldability, and can improve water resistance by irradiating active energy rays, such as EB and an ultraviolet-ray, and its manufacturing method.

  The present inventor originally made a combination of a 1,2-diol PVA resin having a specific saponification degree that is difficult to achieve water resistance in combination with an AA-PVA resin having a specific saponification degree that is difficult to mold in the first place. Surprisingly, the resin composition can be melt-molded, and the melt-formed product can be improved in water resistance by irradiating active energy rays such as EB and ultraviolet rays, thereby completing the present invention. It came to do.

〔式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６はそれぞれ独立して水素原子又は炭素数１〜５のアルキル基を示し、Ｘは単結合又は結合鎖を示す。〕 That is, the present invention has a saponification degree of 80 to 95 mol%, a polyvinyl alcohol resin (A) having a 1,2-diol structural unit represented by the following general formula (1), and a saponification degree. The present invention provides a molded article obtained by melt-molding a resin composition containing 80 to 95 mol% of a polyvinyl alcohol resin (B) containing an acetoacetyl group.

[Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and X represents a single bond or a bonded chain. ]

  In the present invention, the saponification degree is 80 to 95 mol%, the polyvinyl alcohol resin (A) having a 1,2-diol structural unit represented by the general formula (1), and the saponification degree A method for producing a molded product comprising melt-molding a resin composition containing 80 to 95 mol% of a polyvinyl alcohol resin (B) containing an acetoacetyl group at a melting temperature of 100 to 150 ° C. It is to provide.

  The molded product of the present invention can be melt-molded by using a 1,2-diol PVA-based resin having a specific saponification degree and an AA-PVA-based resin having a specific saponification degree. It can be set as a molded product while having it. Therefore, by irradiating such molded articles with active energy rays such as EB and ultraviolet rays, it is presumed that acetoacetyl groups are self-crosslinked and water resistance is improved.

  Since the molded product of the present invention can be produced by melt molding, further development of applications can be expected. Moreover, since the molded article of the present invention can improve water resistance by irradiation with active energy rays such as EB and ultraviolet rays, it can be used for applications requiring water resistance.

  The present invention will be described in detail below, but these show examples of desirable embodiments. In the present specification, (meth) allyl represents allyl or methallyl, (meth) acryl represents allyl or methacryl, and (meth) acrylate represents acrylate or methacrylate.

  The molded article of the present invention has a saponification degree of 80 to 95 mol% and a PVA resin (A) having a 1,2-diol structural unit represented by the following general formula (1), and a saponification degree. It is 80-95 mol%, and is obtained by melt-molding a resin composition containing a PVA resin (B) containing an acetoacetyl group. Hereinafter, each component will be described.

[1,2-diol PVA resin (A)]
The 1,2-diol PVA resin (A) used in the present invention is a PVA resin having a 1,2-diol structural unit represented by the following general formula (1). In the general formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and X represents a single bond or a bonded chain.

  The content (modification rate) of the 1,2-diol structural unit represented by the general formula (1) of the 1,2-diol PVA resin (A) is usually 0.1 to 10 mol%, preferably Is 0.5 to 8 mol%, more preferably 3 to 8 mol%. If the modification rate is too low, melt molding tends to be difficult, and if it is too high, the strength of the molded product tends to decrease. The portions other than the 1,2-diol structural unit are a vinyl alcohol structural unit and a slight amount of vinyl acetate structural unit as in the case of a normal PVA resin.

R ^{1 to} R ⁶ in the 1,2-diol structural unit represented by the general formula (1) are preferably all hydrogen atoms, but if the amount does not significantly impair the resin properties, the number of carbon atoms is 1. May be substituted with ~ 5 alkyl groups. Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, and a pentyl group. It may have a substituent such as a group, a hydroxyl group, an ester group, a carboxylic acid group, or a sulfonic acid group.

Further, X in the 1,2-diol structural unit represented by the general formula (1) is typically a single bond, and is most preferably a single bond from the viewpoint of thermal stability. A binding chain may be used as long as it does not inhibit the above. Such a linking chain is not particularly limited, but hydrocarbons such as alkylene, alkenylene, alkynylene, phenylene, naphthylene and the like (these hydrocarbons may be substituted with halogen such as fluorine, chlorine, bromine, etc.),- _{O -, - (CH 2 O} ) m -, - (OCH 2) m -, - (CH 2 O) m CH 2 -, - CO -, - COCO -, - CO (CH 2) m CO -, - _{CO (C 6 H 4) CO} -, - S -, - CS -, - SO -, - SO 2 -, - NR -, - CONR -, - NRCO -, - CSNR -, - NRCS -, - NRNR- _{, -HPO 4 -, - Si (} OR) 2 -, - OSi (OR) 2 -, - OSi (OR) 2 O -, - Ti (OR) 2 -, - OTi (OR) 2 -, - OTi ( _{OR) 2 O -, - Al} (OR) -, - OAl ( R)-, -OAl (OR) O-, etc. (R is each independently an arbitrary substituent, preferably a hydrogen atom or an alkyl group, and m is a natural number). Alternatively, an alkylene group having 6 or less carbon atoms, particularly a methylene group or —CH ₂ OCH ₂ — is preferable from the viewpoint of stability during use.

〔式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６はそれぞれ独立して水素原子又は炭素数１〜５のアルキル基を示し、Ｘは単結合又は結合鎖を示し、Ｒ^７及びＲ^８はそれぞれ独立して水素原子又はＲ^９−ＣＯ−（式中、Ｒ^９はアルキル基である。）を示す。〕 The production method of the 1,2-diol PVA resin (A) used in the present invention is not particularly limited, but (i) a copolymer of a vinyl ester monomer and a compound represented by the following general formula (2) is used. A saponification method is preferably used.

[Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, X represents a single bond or a bond chain, R ⁷ and R ⁸ each independently represent a hydrogen atom or R ⁹ —CO— (wherein R ⁹ is an alkyl group). ]

〔式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６はそれぞれ独立して水素原子又は炭素数１〜５のアルキル基を示し、Ｘは単結合又は結合鎖を示す。〕
（ｉｉｉ）ビニルエステル系モノマーと下記一般式（４）で示される化合物との共重合体をケン化及び脱ケタール化する方法を用いてもよい。

〔式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６はそれぞれ独立して水素原子又は炭素数１〜５のアルキル基を示し、Ｘは単結合又は結合鎖を示し、Ｒ^１０及びＲ^１１はそれぞれ独立して水素原子又はアルキル基を示す。〕 Moreover, as a manufacturing method other than (i),
(Ii) a method of saponifying and decarboxylating a copolymer of a vinyl ester monomer and a compound represented by the following general formula (3),

[Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and X represents a single bond or a bonded chain. ]
(Iii) A method of saponifying and deketalizing a copolymer of a vinyl ester monomer and a compound represented by the following general formula (4) may be used.

[Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, X represents a single bond or a bond chain, R ¹⁰ and R ¹¹ each independently represent a hydrogen atom or an alkyl group. ]

The vinyl ester monomers used in the present invention include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate. , Vinyl benzoate, vinyl versatate, and the like, among which vinyl acetate is preferably used from the economical viewpoint.
Hereinafter, the methods (i), (ii), and (iii) will be described.

[Method (i)]
In the method (i), a vinyl ester monomer and a compound represented by the general formula (2) are copolymerized and then saponified to have a 1,2-diol structural unit represented by the general formula (1). This is a method for producing a PVA resin (A).
In the compound represented by the general formula (2), R ^{1 to} R ⁶ and X are the same as those in the general formula (1), and R ⁷ and R ⁸ are each independently a hydrogen atom or R ⁹ —CO— (wherein R ⁹ is an alkyl group, preferably a methyl group, a propyl group, a butyl group, a hexyl group or an octyl group. Such an alkyl group has an adverse effect on the copolymerization reactivity and the subsequent steps. As long as there is no substituent, it may have a substituent such as a halogen group, a hydroxyl group, an ester group, a carboxylic acid group, or a sulfonic acid group.

Specific examples of the compound represented by the general formula (2) include 3,4-dihydroxy-1-butene, 3,4-diasiloxy-1-butene, and 3-acyloxy-4-hydroxy-, where X is a single bond. 1-butene, 4-acyloxy-3-hydroxy-1-butene, 3,4-diacyloxy-2-methyl-1-butene, 4,5-dihydroxy-1-pentene, wherein X is an alkylene group, 4,5- Diacyloxy-1-pentene, 4,5-dihydroxy-3-methyl-1-pentene, 4,5-diacyloxy-3-methyl-1-pentene, 5,6-dihydroxy-1-hexene, 5,6-diacyloxy- 1-hexene, X is _-CH 2 OCH ₂ - or -OCH ₂ - in which glycerol monoallyl ether, 2,3-diacetoxy-1-allyloxypropane, 2-a Butoxy-1-allyloxy-3-hydroxypropane, 3-acetoxy-1-allyloxy-2-hydroxypropane, glycerin monovinyl ether, glycerin monomethyl isopropenyl ether and the like.

Among them, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ are hydrogen atoms, X is a single bond, and R ⁷ is excellent in copolymerization reactivity and industrial handling. , R ⁸ is R ⁹ —CO—, and R ⁹ is an alkyl group, preferably 3,4-diacyloxy-1-butene, and in particular, R ⁹ is a methyl group, 3,4-diacetoxy-1- Butene is preferably used. The reactivity ratio (r) of each monomer when vinyl acetate and 3,4-diacetoxy-1-butene were copolymerized was r (vinyl acetate) = 0.710, r (3,4-diacetoxy- 1 butene) = 0.701, which is a reactivity ratio (r) in the case of vinyl ethylene carbonate described later, r (vinyl acetate) = 0.85, and comparison with r (vinyl ethylene carbonate) = 5.4 Therefore, 3,4-diacetoxy-1-butene is more excellent in copolymerization reactivity with vinyl acetate.

As for 3,4-diacetoxy-1-butene, a product of Eastman Chemical Co., Ltd. can be obtained from the market for industrial production, and a product of Acros Co. can be obtained from the reagent level. Further, 3,4-diacetoxy-1-butene obtained as a by-product during the production process of 1,4-butanediol can also be used.
Further, a method for converting 1,4-diacetoxy-2-butene to 3,4-diacetoxy-1-butene described in JP-A No. 10-212264 or the like, or a method described in International Publication No. 00/24702, It can also be obtained by using a known technique such as a method for obtaining 3,4-diacetoxybutene from 3-butadiene via a monoepoxide.

There are no particular limitations on the copolymerization of the vinyl ester monomer and the compound represented by the general formula (2), and known methods such as bulk polymerization, solution polymerization, suspension polymerization, dispersion polymerization, or emulsion polymerization are used. In general, solution polymerization is performed.
The method for charging the monomer component at the time of copolymerization is not particularly limited, and any method such as batch charging, split charging, continuous charging, etc. is adopted, but 1,2-derived from the compound represented by the general formula (2) Drop polymerization is preferred from the viewpoint that the diol structural unit is uniformly distributed in the molecular chain of the polyvinyl ester polymer, and the polymerization method based on the HANNA method using the reactivity ratio with vinyl acetate is particularly preferred.
In addition, dropping polymerization is a method in which either one or both monomers are polymerized while dropping continuously or discontinuously in order to keep the monomer ratio in the reaction system in a certain range during copolymerization, In particular, in the dropping polymerization by the HANNA method, the monomer dropping is performed at a rate commensurate with the monomer consumption rate calculated based on the reactivity ratio of the two monomers, and the monomer ratio in the system is kept almost constant.

Examples of the solvent used in such copolymerization include usually lower alcohols such as methanol, ethanol, isopropyl alcohol, n-propanol and butanol, and ketones such as acetone and methyl ethyl ketone, and industrially preferred is methanol. used.
The amount of the solvent used may be appropriately selected in consideration of the chain transfer constant of the solvent in accordance with the degree of polymerization of the target copolymer. For example, when the solvent is methanol, S (solvent) / M ( Monomer) = 0.01 to 10 (weight ratio), preferably selected from the range of about 0.04 to 3 (weight ratio).

For the copolymerization, a polymerization catalyst is used. Examples of the polymerization catalyst include known radical polymerization catalysts such as azobisisobutyronitrile, acetyl peroxide, benzoyl peroxide, lauryl peroxide, azobisdimethylvaleronitrile, azo And low temperature active radical polymerization catalysts such as bismethoxydimethylvaleronitrile and t-butylperoxyneodecanoate. The amount of polymerization catalyst used varies depending on the type of comonomer and the type of catalyst and cannot be determined unconditionally, but is arbitrarily selected according to the polymerization rate. For example, when azoisobutyronitrile or acetyl peroxide is used, 0.002 to 0.7 mol% is preferable with respect to the vinyl ester monomer, and 0.004 to 0.5 mol% is particularly preferable.
Moreover, the reaction temperature of a copolymerization reaction is performed at about 30 degreeC-a boiling point by the solvent and pressure to be used, More specifically, it is 35-90 degreeC, Preferably it is carried out in 40-75 degreeC.

  The resulting copolymer is then saponified. In the saponification, the copolymer obtained as described above is dissolved in a solvent such as alcohol, and an alkali catalyst or an acid catalyst is used. Typical solvents include methanol, ethanol, propanol, tert-butanol and the like, and methanol is particularly preferably used. The concentration of the copolymer in the alcohol is appropriately selected depending on the viscosity of the system, but is usually selected from the range of 10 to 60% by weight. Catalysts used for saponification include alkali catalysts such as alkali metal hydroxides and alcoholates such as sodium hydroxide, potassium hydroxide, sodium methylate, sodium ethylate, potassium methylate, lithium methylate, etc., sulfuric acid, Examples include acid catalysts such as hydrochloric acid, nitric acid, metasulfonic acid, zeolite, and cation exchange resin.

The amount of the saponification catalyst used is appropriately selected depending on the saponification method, the target degree of saponification, and the like. Usually, when an alkali catalyst is used, the vinyl ester monomer and the general formulas (2) to (4) are used. The ratio of 0.1 to 30 mmol, preferably 2 to 17 mmol, is appropriate with respect to 1 mol of the total amount of 1,2-diol structural units derived from the compound represented by (1).
Moreover, although the reaction temperature of saponification reaction is not specifically limited, 10-60 degreeC is preferable, More preferably, it is 20-50 degreeC.

  The 1,2-diol PVA resin (A) obtained by the method (i) differs from the methods (ii) and (iii), and an acetoxy group remains in the side chain depending on the degree of saponification. Since such a side chain acetoxy group is larger than the side chain hydroxyl group and has a higher degree of freedom than the main chain acetoxy group, the crystallinity inhibition of the PVA resin, the interface characteristics when used in an aqueous solution, or the affinity with other materials, etc. It is estimated that the effect on is great.

  In addition, the 1,2-diol PVA resin (A) obtained by the method (ii) or (iii) has a side chain when the degree of saponification is low or when decarboxylation or deacetalization is insufficient. A carbonate ring or an acetal ring may remain, and these may react with other additives in the resin composition and impair the stability. On the other hand, the 1,2-diol PVA-based resin (A) by the method (i) does not have the above-mentioned problems, and is excellent in terms of stability at the time of production and after becoming a product.

[Method (ii)]
In the method (ii), a vinyl ester monomer and a compound represented by the above general formula (3) are copolymerized, then saponified and decarboxylated, and then 1,2-diol represented by the above general formula (1). This is a method for producing a PVA-based resin having a structural unit.
In the compound represented by the general formula (3) used in the present invention, examples of R ^{1 to} R ⁶ and X are the same as those in the general formula (1). Among them, vinyl ethylene carbonate in which R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ are hydrogen atoms and X is a single bond is preferable in terms of easy availability and good copolymerizability. Used for.

Copolymerization and saponification of the vinyl ester monomer and the compound represented by the general formula (3) are performed in the same manner as in the above method (i).
In addition, about decarboxylation, without performing a special process, decarboxylation is performed with saponification, and it transform | converts into a 1, 2- diol structure by opening an ethylene carbonate ring.
It is also possible to perform decarboxylation without saponifying the vinyl ester moiety under a constant pressure (normal pressure to 1 × 10 ⁷ Pa) and at a high temperature (50 to 200 ° C.). The saponification can also be performed after carbonation.

[Method (iii)]
In the method (iii), a vinyl ester monomer and a compound represented by the above general formula (4) are copolymerized and then saponified and deketalized to obtain a 1,2-diol represented by the above general formula (1). This is a method for producing a PVA-based resin having a structural unit.
In the compound represented by the general formula (4) used in the present invention, R ^{1 to} R ⁶ and X are the same as those in the general formula (1), and R ¹⁰ and R ¹¹ are each independently hydrogen. An atom or an alkyl group. Although it does not specifically limit as this alkyl group, For example, C1-C4 alkyl groups, such as a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, are preferable. Such an alkyl group may have a substituent such as a halogen group, a hydroxyl group, an ester group, a carboxylic acid group, or a sulfonic acid group as long as the copolymerization reactivity and the like are not impaired. Among them, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ are hydrogen and R ¹⁰ , R ¹¹ are methyl groups in terms of easy availability and good copolymerizability. 2-Dimethyl-4-vinyl-1,3-dioxolane is preferred.

Copolymerization and saponification of the vinyl ester monomer and the compound represented by the general formula (4) are performed in the same manner as in the method (i).
As for deketalization, when the saponification reaction is carried out using an alkali catalyst, an aqueous solvent (lower alcohol mixed solvent such as water, water / acetone, water / methanol, etc.) is used after further saponification using an acid catalyst. Etc.) is deketalized and converted to a 1,2-diol structure. In this case, examples of the acid catalyst include acetic acid, hydrochloric acid, sulfuric acid, nitric acid, metasulfonic acid, zeolite, and cation exchange resin.
Moreover, when a saponification reaction is performed using an acid catalyst, deketalization is performed with saponification, without performing a special process, and is converted into a 1,2-diol structure.

In addition, the 1,2-diol PVA resin (A) used in the present invention may be a copolymer obtained by copolymerizing various unsaturated monomers as long as the object of the present invention is not hindered, particularly as long as the aqueous solution does not decrease. . The amount of the unsaturated monomer introduced cannot be generally determined, but if the amount introduced is too large, the water solubility tends to be impaired.
Examples of the unsaturated monomer include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, α-octadecene, acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid and the like. Unsaturated acids, their salts, monoesters or dialkyl esters, nitriles such as acrylonitrile and methacrylonitrile, amides such as diacetone acrylamide, acrylamide and methacrylamide, ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, etc. Olefin sulfonic acids or salts thereof, alkyl vinyl ethers, dimethylallyl vinyl ketone, N-vinyl pyrrolidone, vinyl compounds such as vinyl chloride, substituted vinyl acetates such as isopropenyl acetate and 1-methoxyvinyl acetate. Le ethers, vinylidene chloride, 1,4-diacetoxy-2-butene, vinylene carbonate, acetoacetyl group-containing monomers.

Furthermore, polyoxyethylene (meth) allyl ether, polyoxyethylene (meth) acrylamide, polyoxypropylene (meth) acrylamide, polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, polyoxyethylene (1- ( Poly) alkylene groups such as (meth) acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene vinyl ether, polyoxyethylene allylamine, polyoxypropylene allylamine, polyoxyethylene vinylamine, polyoxypropylene vinylamine Containing monomer, N-acrylamidomethyltrimethylammonium chloride, N-acrylamidoethyltrimethylammonium chloride, N-acrylic Amidopropyltrimethylammonium chloride, 2-acryloxyethyltrimethylammonium chloride, 2-methacryloxyethyltrimethylammonium chloride, 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, 3- Examples also include cation group-containing monomers such as butenetrimethylammonium chloride, dimethyldiallylammonium chloride, and diethyldiallylammonium chloride.
Moreover, it is possible to use what introduce | transduced about 1.6-3.5 mol% of 1, 2-diol bond in the PVA main chain by making superposition | polymerization temperature into 100 degreeC or more.

The viscosity of the 1,2-diol PVA resin (A) is usually 1.5 to 20 mPa · s, preferably 3 to 12 mPa · s, and particularly preferably 4 to 8 mPa · s. If the viscosity is too low, the strength of the molded product tends to decrease, and if it is too high, the viscosity of the resin composition becomes too high and melt molding tends to be difficult.
In the present specification, the viscosity of the 1,2-diol PVA resin (A) is a viscosity of a 4% by weight aqueous solution at 20 ° C. measured in accordance with JIS K 6726.

  The average degree of polymerization (measured according to JIS K 6726) of the 1,2-diol PVA resin (A) is usually 300 to 4000, preferably 300 to 2000, and particularly preferably 400 to 1000. is there. If the average degree of polymerization is too low, the strength of the molded product tends to decrease, and if it is too high, the viscosity of the resin composition becomes too high and melt molding tends to be difficult.

The saponification degree of the 1,2-diol PVA resin (A) is 80 to 95 mol%, preferably 82 to 93 mol%, particularly preferably 85 to 90 mol%. If the degree of saponification is too high, melt molding tends to be difficult, and if it is too low, water solubility tends to decrease.
The saponification degree can be measured according to JIS K 6726.

[AA-PVA resin (B)]
The AA-PVA resin (B) used in the present invention is a PVA resin having an acetoacetyl group in the side chain, and has, for example, a structural unit represented by the following formula (5).

  Although it does not specifically limit as a manufacturing method of this AA-PVA type-resin (B), For example, PVA type-resin and the diketene are made to react, PVA-type resin and acetoacetic ester are made to react, and transesterification is carried out. And a method of saponifying a copolymer of vinyl acetate and vinyl acetoacetate. In particular, since the production process is simple and an AA-PVA resin having good quality is obtained, it is preferable to produce the resin by a method of reacting the PVA resin and diketene. Hereinafter, this method will be described.

  As the PVA resin used as a raw material, a saponified polymer of vinyl ester monomer or a derivative thereof is generally used. Such vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, versatic. Although vinyl acid acid etc. are mentioned, vinyl acetate is preferably used from the point of economical efficiency.

  A saponified product of a copolymer of a vinyl ester monomer and a monomer copolymerizable with the vinyl ester monomer can also be used. Examples of the copolymerizable monomer include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, α-octadecene, 3-buten-1-ol, 4-penten-1-ol, and 5-hexene- Hydroxyl group-containing α-olefins such as 1-ol and 3,4-dihydroxy-1-butene, and derivatives such as acylated products thereof, acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, undecylene Unsaturated acids such as acids, their salts, monoesters, dialkyl esters, nitriles such as acrylonitrile and methacrylonitrile, amides such as diacetone acrylamide, acrylamide and methacrylamide, ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfone Olefin such as acid Vinyls such as phonic acids or salts thereof, alkyl vinyl ethers, dimethylallyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinyl ethylene carbonate, 2,2-dialkyl-4-vinyl-1,3-dioxolane, glycerol monoallyl ether Examples thereof include compounds, substituted vinyl acetates such as isopropenyl acetate and 1-methoxyvinyl acetate, vinylidene chloride, 1,4-diacetoxy-2-butene, 1,4-dihydroxy-2-butene, and vinylene carbonate.

Furthermore, polyoxyethylene (meth) allyl ether, polyoxyethylene (meth) acrylamide, polyoxypropylene (meth) acrylamide, polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, polyoxyethylene (1- ( Poly) alkylene groups such as (meth) acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene vinyl ether, polyoxyethylene allylamine, polyoxypropylene allylamine, polyoxyethylene vinylamine, polyoxypropylene vinylamine Containing monomer, N-acrylamidomethyltrimethylammonium chloride, N-acrylamidoethyltrimethylammonium chloride, N-acrylic Amidopropyltrimethylammonium chloride, 2-acryloxyethyltrimethylammonium chloride, 2-methacryloxyethyltrimethylammonium chloride, 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, 3- Examples also include cation group-containing monomers such as butenetrimethylammonium chloride, dimethyldiallylammonium chloride, and diethyldiallylammonium chloride.
The introduction amount of the copolymerization monomer varies depending on the kind of the monomer, and thus cannot be generally specified. However, it is usually less than 10 mol%, particularly less than 5 mol% of all structural units, and if it is too much, water solubility is impaired. Or the compatibility with the crosslinking agent tends to decrease.

  In addition, by increasing the polymerization temperature when polymerizing and copolymerizing vinyl ester monomers and other monomers, the amount of heterogeneous bonds generated with respect to 1,3-bonds that are mainly generated is increased, and 1 in the PVA main chain is increased. , 2-diol bond having a content of about 1.6 to 3.5 mol% can be used.

  Introducing acetoacetyl groups by reaction of PVA resin obtained by saponifying the polymer and copolymer of vinyl ester monomer and diketene, direct reaction of PVA resin with gaseous or liquid diketene. Alternatively, after adsorbing and occluding the organic acid in the PVA resin in advance, gaseous or liquid diketene is sprayed and reacted in an inert gas atmosphere, or a mixture of organic acid and liquid diketene is added to the PVA resin. Methods such as spraying and reacting are used.

  As a reaction apparatus for carrying out the above reaction, an apparatus capable of heating and equipped with a stirrer can be used. For example, a kneader, a Henschel mixer, a ribbon blender, other various blenders, and a stirring and drying apparatus can be used.

The viscosity of the AA-PVA resin (B) is usually 1.5 to 20 mPa · s, preferably 2.5 to 12 mPa · s, and particularly preferably 3 to 8 mPa · s. If the viscosity is too low, the strength of the molded product tends to decrease, and if it is too high, the viscosity of the resin composition becomes too high and melt molding tends to be difficult.
In the present specification, the viscosity of the AA-PVA resin (B) is a viscosity of a 4 wt% aqueous solution at 20 ° C. measured in accordance with JIS K 6726.

  The average degree of polymerization (measured according to JIS K 6726) of the AA-PVA resin (B) is usually 300 to 4000, preferably 300 to 1500, particularly preferably 300 to 800. If the average degree of polymerization is too low, the water resistance tends to decrease. If the average degree of polymerization is too high, the viscosity of the resin composition becomes too high and production tends to be difficult.

The degree of saponification of the AA-PVA resin (B) is 80 to 95 mol%, preferably 82 to 93 mol%, particularly preferably 85 to 90 mol%. If the degree of saponification is too high, melt molding tends to be difficult, and if it is too low, water solubility tends to decrease.
The saponification degree can be measured according to JIS K 6726.

  The AA-PVA resin (B) used in the present invention may be one type or a mixture of two or more types, but when a mixture is used, the saponification degree and the average degree of polymerization are average. The value is preferably within the above-mentioned range.

[PVA resin composition]
The PVA resin composition used in the present invention contains a 1,2-diol PVA resin (A) and an AA-PVA resin (B).

  The content ratio (A / B) between the content of the 1,2-diol PVA resin (A) and the content of the AA-PVA resin (B) is usually 9/1 to 1/9 by weight. Preferably, it is 8/2 to 2/8, more preferably 7/3 to 3/7.

The PVA resin composition used in the present invention includes other PVA resins different from the 1,2-diol PVA resin (A) and the AA-PVA resin (B) as long as the effects of the present invention are not impaired. It may contain a resin or other polymer. Other PVA-based resins include those having different contents of the 1,2-diol structural unit represented by the general formula (1), those having different contents of acetoacetyl groups, those having different saponification degrees, and degrees of polymerization. Examples thereof include those different from each other, those having different copolymerization components, those having no modifying group, and other various modified PVAs. Examples of the other polymer include vinyl alcohol resins such as ethylene-vinyl alcohol copolymer; various thermoplastic resins such as polyamide, polyester, polyethylene, polypropylene, and polystyrene.
As content of the above-mentioned PVA-type resin and other polymer, less than 10 weight% with respect to the resin composition of this invention, Especially less than 5 weight% is preferable.

  In addition, the PVA resin composition of the present invention includes a reinforcing agent, a filler, a plasticizer, a pigment, a dye, a lubricant, an antioxidant, and an antistatic agent as necessary, as long as the effects of the present invention are not impaired. Contains UV absorbers, heat stabilizers, light stabilizers, surfactants, antibacterial agents, antistatic agents, drying agents, antiblocking agents, flame retardants, crosslinking agents, curing agents, foaming agents, crystal nucleating agents, etc. May be.

The PVA-based resin composition used in the present invention is usually in the form of pellets or powders for use as a molding material. Among them, the pellet shape is preferable from the viewpoint of small problems of charging into a molding machine, handling, and generation of fine powder.
In addition, although the well-known method can be used for shaping | molding into this pellet shape, the method of extruding in a strand form from an extruder, cut | disconnecting to predetermined length after cooling, and making a cylindrical pellet is efficient.
Moreover, as a magnitude | size of this column-shaped pellet, length is 1-4 mm normally, Preferably it is 2-3 mm, and a diameter is 1-4 mm normally, Preferably it is 2-3 mm.

  The PVA resin composition used in the present invention is, for example, (a) a method of mixing and melting a powder of 1,2-diol PVA resin (A) and a powder of AA-PVA resin (B), ( b) A method of blending and melting the powder of AA-PVA resin (B) in the molten 1,2-diol PVA resin (A), (c) 1, adding to the molten AA-PVA resin (B), It can manufacture by the method of mix | blending the powder of 2-diol PVA-type resin (A), and fuse | melting.

  As a melting method, after mixing with a mixer such as a Henschel mixer or a ribbon blender, a method of melting and kneading with a melt kneader such as a single screw or twin screw extruder, roll, Banbury mixer, kneader, Brabender mixer, etc. It is done. The temperature at the time of melt kneading can be appropriately set within a temperature range that is equal to or higher than the melting points of the PVA resins (A) and (B) and does not thermally deteriorate, but is preferably 100 to 250 ° C., particularly preferably. Is 100-140 ° C.

〔Molding〕
The PVA-based resin composition used in the present invention is useful as a molding material because it is excellent in moldability, particularly melt moldability. As the melt molding method, known molding methods such as extrusion molding, inflation molding, injection molding, blow molding, vacuum molding, pressure molding, compression molding, calender molding, and the like can be used, and a PVA resin composition is melted at a melting temperature of 100. The molded article of the present invention can be produced by melt molding at ˜150 ° C., preferably 110 to 140 ° C., particularly preferably 120 to 130 ° C.
In addition, examples of the molded product of the present invention include various shapes such as films, sheets, pipes, disks, rings, bags, bottles, and fibers.
For example, when used as a film, the thickness is usually 5 to 90 μm, preferably 15 to 70 μm.
Examples of applications of the molded product of the present invention include food and beverage packaging materials, containers, bag-in-box inner bags, container packings, medical infusion bags, organic liquid containers, organic liquid transport pipes, and various gas containers. , Tubes, hoses and the like. Moreover, it can also be used for various electric parts, automobile parts, industrial parts, leisure goods, sports goods, daily goods, toys, medical equipment, sanitary goods, and the like.

  The molded article of the present invention can be improved in water resistance by irradiation with active energy rays. As active energy rays, far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays and other electromagnetic waves, X rays, γ rays and other electromagnetic waves, as well as EB (electron beam), proton rays, neutron rays, etc. can be used. Curing by ultraviolet irradiation is advantageous because of the availability of the irradiation device and the price.

Methods for improving water resistance by ultraviolet irradiation include high pressure mercury lamps that emit light in the 150 to 450 nm wavelength region, ultra high pressure mercury lamps, carbon arc lamps, metal halide lamps, xenon lamps, chemical lamps, electrodeless discharge lamps, LEDs, etc. And a method of irradiating about 30 to 3000 mJ / cm ² .
After ultraviolet irradiation, heat treatment may be performed as necessary.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded. In the examples, “%” and “parts” mean weight basis.

[Example 1]
(1) Production of 1,2-diol PVA resin (A) In a reaction vessel equipped with a reflux condenser, a dropping funnel and a stirrer, 1000 g of vinyl acetate, 50 g of methanol, and 60 g of 3,4-diacetoxy-1-butene (3 mol% with respect to the charged vinyl acetate) was charged, and 0.003 mol% (with respect to the charged vinyl acetate) of azobisisobutyronitrile was added, and the temperature was raised in a nitrogen stream while stirring to initiate polymerization. Further, 0.002 mol% of azobisisobutyronitrile was added 3 hours after the start of polymerization, and when the polymerization rate of vinyl acetate reached 40%, a predetermined amount of m-dinitrobenzene was added to complete the polymerization. Subsequently, by distillation while blowing methanol vapor, unreacted vinyl acetate monomer was removed from the system to obtain a methanol solution of the copolymer.

  Next, the solution was diluted with methyl acetate, adjusted to a concentration of 20%, charged into a kneader, and while maintaining the solution temperature at 40 ° C., a 2% methanol solution of sodium hydroxide was added to the vinyl acetate structural unit and the copolymer. Saponification was carried out by adding 3 mmol per 1 mol of the total amount of 3,4-diacetoxy-1-butene structural units. When saponification progressed as saponification progressed and became particulate, 0.8 equivalent of sodium hydroxide was added to neutralizing acetic acid, filtered, washed well with methanol, and hot air dryer It was then dried to obtain 1,2-diol PVA resin (A).

The saponification degree of the obtained 1,2-diol PVA resin (A) was 88 mol% when analyzed by the alkali consumption required for hydrolysis of residual vinyl acetate and 3,4-diacetoxy-1-butene. Met. The average degree of polymerization was 450, as analyzed according to JIS K 6726. Furthermore, the content of the 1,2-diol structural unit was 6 mol% when calculated by measurement with ¹ H-NMR (internal standard substance: tetramethylsilane). In addition, “AVANCE DPX400” manufactured by Nippon Bruker Co., Ltd. was used for NMR measurement.

(2) Production of AA-PVA (B) In a reaction vessel equipped with a reflux condenser, a dropping funnel, and a stirrer, 1000 parts of vinyl acetate, 300 parts of methanol, and 0.05 mol% of azobisisobutyronitrile (as opposed to charging) Vinyl acetate) was added, the temperature was raised while stirring under a nitrogen stream, and polymerization was carried out at the boiling point for 5 hours. When the polymerization rate of vinyl acetate reached 70%, m-dinitrobenzene was added to complete the polymerization, and then unreacted vinyl acetate monomer was removed from the system by blowing methanol vapor. A combined methanol solution (41% resin content) was obtained.
Subsequently, the solution was diluted with methyl acetate, adjusted to a concentration of 29.5%, charged into a kneader, and neutralized by adding sodium hydroxide while maintaining the solution temperature at 35 ° C. Further, 11 mmol of sodium hydroxide is added to 1 mol of vinyl acetate unit in the polymer to saponify, the precipitate is filtered, washed well with methanol, dried in a hot air dryer, and further at 80 ° C. A PVA resin was obtained by heat treatment for 60 minutes.

The saponification degree of the obtained PVA-based resin was 88 mol% when analyzed by the alkali consumption required for hydrolysis of residual vinyl acetate. The average degree of polymerization was 320 when analyzed according to JIS K 6726. Furthermore, the sodium acetate content was 0.5%.
3600 parts of the PVA resin is charged in a kneader, 540 parts of acetic acid is added to the kneader, and the mixture is swollen. After stirring at 20 rpm, the temperature is raised to 60 ° C., and 420 parts of diketene is added dropwise over 3 hours. The reaction was carried out for 1 hour. After completion of the reaction, the mixture was washed with methanol and then dried at 70 ° C. for 6 hours to obtain AA-PVA resin (B). The AA-PVA resin (B) has a degree of AA conversion of 8.5 mol%, and the degree of saponification and the average degree of polymerization are the same as the PVA resin used.

(3) Production of resin composition After dry blending 45 parts of the 1,2-diol PVA resin (A) and 30 parts of the AA-PVA resin (B), 25 parts of glycerin is injected as a plasticizer. While this was melt-kneaded with a twin screw extruder under the following conditions, extruded into a strand and cut with a pelletizer to obtain a resin composition of a cylindrical pellet.
Diameter (D) 15mm, L / D = 60
Screw rotation speed: 200rpm
Setting temperature: C1 / C2 / C3 / C4 / C5 / C6 / C7 / C8 / D = 120/180/190/195/120/120/120/120/120 ° C.
Screw pattern: 3 kneaded screws Screen mesh: 90/90 mesh
Discharge rate: 1.5kg / hr

(4) Production of Film The obtained pellet was formed into a single-layer PVA film having a thickness of about 30 μm by the following conditions using a twin-screw extruder, and the following evaluation was performed. The results are shown in Table 1.
Diameter (D) 15mm, L / D = 60
Screw rotation speed: 200rpm
Setting temperature: C1 / C2 / C3 / C4 / C5 / C6 / C7 / C8 / D = 110/120/120/120/120/120/120/120/140 ° C.
Discharge rate: 1.5kg / hr
Screen mesh: 90/90 mesh
Die: width 300mm, coat hanger type take-up speed: 2.6m / min
Roll temperature: 50 ° C
Air gap: 1cm

(5) Ultraviolet irradiation process By irradiating ultraviolet rays with respect to said PVA film on the irradiation conditions shown below, the crosslinking reaction of AA-PVA type-resin (B) itself was caused.
(Irradiation conditions)
Irradiation equipment: High pressure mercury lamp 80W
Irradiation amount: 3000 mJ / cm ²
Irradiation distance to film: 130mm
UV irradiation time: 50 seconds UV irradiation atmosphere: atmosphere temperature 30 ° C., atmosphere humidity 50% RH

<Evaluation method>
(Film forming property)
About the PVA film before ultraviolet irradiation, the external appearance was observed visually and the film forming property was evaluated on the following reference | standard.
○ ・ ・ It is a uniform film with no holes.
△ ・ ・ There is no hole, but it is a non-uniform film.
× ·· A hole is opened and a net-like film.

(Water soluble)
The time until the PVA film (2.5 × 5.0 × 0.03 mm) was completely dissolved in 2 L of water at 20 ° C. was measured before and after the ultraviolet irradiation in the above (5). The results are shown in Table 1.

[Example 2]
In Example 1, a PVA film was prepared in the same manner as in Example 1 except that an AA-PVA resin (B) having an AA conversion of 3.5 mol%, a saponification degree of 88 mol%, and an average polymerization degree of 320 was used. Manufactured and similarly evaluated.

Example 3
In Example 1, a PVA film was prepared in the same manner as in Example 1 except that an AA-PVA resin (B) having an AA conversion of 8.5 mol%, a saponification degree of 88 mol%, and an average polymerization degree of 550 was used. Manufactured and similarly evaluated.

Example 4
In Example 1, a PVA film was produced in the same manner as in Example 1 except that 30 parts of the 1,2-diol PVA resin (A) and 45 parts of the AA-PVA resin (B) were used. Was done.

[Comparative Example 1]
In Example 1, a PVA film was produced in the same manner as in Example 1 except that the AA-PVA resin (B) was not blended, and evaluation was performed in the same manner.

[Comparative Example 2]
In Example 3, a PVA film was produced in the same manner as in Example 1 except that the 1,2-diol PVA-based resin (A) was not blended, and was evaluated in the same manner. In the production of the above (3) resin composition, the maximum set temperature was changed to 170 ° C.

[Discussion]
In the PVA films of Examples 1 to 4 according to the molded article of the present invention, all were excellent in melt moldability, and the water resistance was remarkably improved by irradiation with ultraviolet rays.
On the other hand, the PVA film of Comparative Example 1 consisting only of the 1,2-diol PVA resin (A) has low water resistance and could not improve water resistance even when irradiated with ultraviolet rays. Moreover, in the PVA film of the comparative example 2 which consists only of AA-PVA-type resin (B), film forming property was bad and it was inferior to melt moldability.

  Since the molded product of the present invention can be produced by melt molding, further development of applications can be expected. Moreover, since the molded article of the present invention can improve water resistance by irradiation with active energy rays such as ultraviolet rays, it can be used for applications requiring water resistance.

Claims (3)

A polyvinyl alcohol resin (A) having a saponification degree of 80 to 95 mol% and having a 1,2-diol structural unit represented by the following general formula (1), and a saponification degree of 80 to 95 mol% A molded product obtained by melt-molding a resin composition containing a polyvinyl alcohol resin (B) containing an acetoacetyl group.

[Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and X represents a single bond or a bonded chain. ]   The content ratio (weight) of the polyvinyl alcohol resin (A) having a 1,2-diol structural unit and the polyvinyl alcohol resin (B) containing an acetoacetyl group is 9/1 to 1/9. The molded article according to claim 1. A polyvinyl alcohol resin (A) having a saponification degree of 80 to 95 mol% and having a 1,2-diol structural unit represented by the following general formula (1), and a saponification degree of 80 to 95 mol% A method for producing a molded product, comprising melt-molding a resin composition containing a polyvinyl alcohol-based resin (B) containing an acetoacetyl group at a melting temperature of 100 to 150 ° C.

[Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and X represents a single bond or a bonded chain. ]