JP4689000B2 - Polyvinyl alcohol moldings - Google Patents

Description

このフィルムを用いて、以下の評価試験を行った。試験結果は、表１に示したように強度、伸度ともに充分高く、異臭や熱分解による着色は全くなかった。
【００３２】
評価試験
１．フィルムの強度、伸度
上記フィルムを２０℃、６５％ＲＨにて２４時間調湿し、その後、東洋精機（株）製ストログラフＲ３型を用いて、チャック間距離３０ｍｍ、引張速度５０ｍｍ／分の条件下でフィルムが破断するときの強度および伸度を測定した。
２．耐黄変度
上記フィルムを日本電色工業（株）の分光式色差計ＣＯＨ−３００Ａを用いて透過光の黄色度（ＹＩ）を測定して、以下の基準で耐黄変度を評価した。
◎：ＹＩ＝１．０未満
○：ＹＩ＝１．０〜３．０未満
△：ＹＩ＝３．０〜１０．０
×：ＹＩ＝１０．０を越える
３．異臭
上記フィルムの匂いについて以下の基準で評価した。
◎：全く匂いが感じられない。
○：ほとんど匂いが感じられない。
△：ＰＶＡの分解臭が感じられる。
×：激しいＰＶＡの分解臭がする。
４．総合評価
上記の各評価を総合的に以下の基準で総合評価した。
◎：熱分解による着色や分解ガスによる異臭の発生が全くなく、フィルムの強度、伸度ともに高い。
○：熱分解による着色や分解ガスによる異臭の発生がほとんどなく、フィルムの強度、伸度ともに高い。
×：熱分解による着色や分解ガスによる異臭の発生、フィルムの強度、伸度のうち１つ以上の性能が劣っている。
【００３３】
実施例２
アジピン酸ジヒドラジドの配合量を７重量部に変えた以外は、実施例１と同様の方法でフィルムを得た。このフィルムを用いて実施例１と同様にして評価試験を行った。結果は表１に示したように強度、伸度ともに充分高く、異臭や熱分解による着色もなかった。
【００３４】
実施例３
アジピン酸ジヒドラジドの配合量を０．３重量部に変えた以外は、実施例１と同様の方法でフィルムを得た。このフィルムを用いて実施例１と同様にして評価試験を行った。結果は表１に示したように強度、伸度ともに充分高く、異臭や熱分解による着色もなかった。
【００３５】
実施例４
ヒドラジン化合物をセバシン酸ジヒドラジドに変えた以外は、実施例１と同様の方法でフィルムを得た。このフィルムを用いて実施例１と同様にして評価試験を行った。結果は表１に示したように強度、伸度ともに充分高く、異臭や熱分解による着色もなかった。
【００３６】
実施例５
ＰＶＡ樹脂を平均重合度６００、ケン化度９８．４モル％のものに変え、製膜条件を以下に示すものに変更した以外は、実施例１と同様の条件にてフィルムを得た。
このフィルムを用いて、実施例１と同様にして評価試験を行った。結果は表１に示したように強度、伸度ともに充分高く、異臭や熱分解による着色もなかった。

このフィルムを用いて、実施例１と同様にして評価試験を行った。試験結果は、表１に示したように強度、伸度ともに充分高く、異臭や熱分解による着色はなかった。
【００３７】
実施例６
ＰＶＡ樹脂（平均重合度１０００、ケン化度８７．４モル％）１００重量部とヒドラジン化合物としてのアジピン酸ジヒドラジド粉末４重量部とをドライブレンドした。このＰＶＡ樹脂組成物をインフレーション製膜機を用いて、溶融成形することにより厚さ４０μｍ、折り幅１３ｃｍのフィルムを得た。この時の製膜条件を以下に示す。
【００３８】
実施例７
ＰＶＡ樹脂を平均重合度６００、ケン化度９８．４モル％のものに変え、製膜条件を以下に示すものに変更した以外は、実施例６と同様の条件にてフィルムを得た。
このフィルムを用いて、実施例１と同様にして評価試験を行った。結果は表１に示したように強度、伸度ともに充分高く、異臭や熱分解による着色もなかった。
（製膜条件）
シリンダー温度： ２３５℃
ダイス温度： ２２５℃
スクリュー回転速度：３０ｒｐｍ
吐出量： １５ｇ／ｍｉｎ
【００３９】
比較例１
ヒドラジン化合物を添加しなかった以外は実施例１と同様にしてフィルムを作成した。このフィルムを用いて、実施例１と同様にして評価試験を行った。結果は表１に示したように、フィルムに熱分解による激しい着色や分解ガスによる激しい異臭の発生があった。
【００４０】
比較例２
アジピン酸ジヒドラジドの配合量を０．０１重量部に変えた以外は、実施例１と同様にしてフィルムを作成した。このフィルムを用いて、実施例１と同様にして評価試験を行った。結果は表１に示したように、分解防止効果は十分ではなく、フィルムは熱分解による着色や分解ガスによる異臭の発生があった。
【００４１】
比較例３
ヒドラジン化合物を添加しなかった以外は実施例５と同様にしてフィルムを作成した。成形中におけるＰＶＡの分解が激しく、フィルムを得ることはできなかった。
【００４２】
比較例４
ヒドラジン化合物を添加しなかった以外は実施例６と同様にしてフィルムを作成した。このフィルムを用いて、実施例１と同様にして評価試験を行った。結果は、表１に示したように、フィルムは熱分解による着色や分解ガスによる異臭の発生があった。
【００４３】
【表１】

【００４４】
【発明の効果】
本発明によれば、ＰＶＡが本来有している強度等の機械的物性に優れるＰＶＡ成形体を熱分解による着色および異臭を発生することなく、熱溶融成形により工業的に容易に得ることができる。[0001]
BACKGROUND OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention can be easily obtained industrially by hot melt molding without causing coloring or off-flavor due to thermal decomposition, and is a machine such as strength inherent in polyvinyl alcohol (hereinafter abbreviated as PVA). The present invention relates to a PVA-based molded article having excellent physical properties.
[0002]
[Prior art]
Since the melting point of PVA is very close to the thermal decomposition temperature, melt molding, which is performed with ordinary thermoplastic resins, has problems such as coloring due to thermal decomposition and off-flavors due to decomposition products, and is hardly performed. . Therefore, when obtaining a molded body from PVA, for example, when obtaining a film from PVA, a method for producing a film by casting by dissolving water or PVA in an organic solvent that can be dissolved is generally performed. . However, in this method, it is necessary to dry a large amount of water or an organic solvent used for dissolving PVA, the production process is complicated and production efficiency is poor, and furthermore, a large amount of heat energy is required for drying. There was a problem that became high.
[0003]
As a method for obtaining a PVA-based molded article by melt molding, conventionally, a method has been proposed in which a large amount of a plasticizer such as water, glycerin or polyethylene glycol is added to lower the melting point and the melt viscosity. However, when a large amount of water is used, a drying step is required. When a large amount of plasticizer is used, the obtained molded product is sticky and easily causes blocking. There is a problem that the physical properties are impaired.
[0004]
In addition, many methods have been proposed for enabling melt molding by lowering the melting point of PVA by copolymerization of PVA with other monomers or by chemically modifying PVA with other functional groups and then modifying. For example, Japanese Laid-6-136138 discloses a method using a PVA having an acrylic alcohol units, in JP flat 9-272719, a method of using PVA having an α- olefin units, in JP-A 3-203932 JP A method using PVA containing an oxyalkylene group has been proposed. However, in these methods, it is necessary to produce PVA under special conditions, or further chemical treatment is required after producing PVA, which increases the production cost of PVA-based resin, and produces PVA. There is a drawback that the process becomes complicated.
[0005]
Many proposals have also been made on a method of performing melt molding by adding a PVA thermal decomposition inhibitor. For example, an acid having a PKa of 5.0 or less is added in an amount of 0.1 to 10 moles per mole of PVA alkali metal salt, the alkali metal salt contained in PVA is dissociated, and acetic acid is excluded from the PVA system. Although there is a method (Japanese Patent Laid-Open No. 6-136139), this method requires a mechanism for removing acetic acid generated in the melt molding machine, and such a mechanism is generally used in a melt extrusion molding machine generally used. Therefore, there are two steps, ie, a step of eliminating acetic acid and a step of actually performing extrusion molding, and there are problems that the molding equipment becomes complicated and the manufacturing cost increases.
[0006]
In addition, methods for adding a metal salt such as lithium chloride as a thermal decomposition inhibitor for PVA have been proposed (Japanese Patent Laid-Open No. 4-202535), but these methods are not sufficient in preventing thermal decomposition. is there.
[0007]
As described above, various studies have been made in the past regarding methods for melt-molding PVA-based resins. However, there are still few examples of producing molded products of PVA-based resins by melt-molding. It is.
[0008]
[Problems to be solved by the invention]
The present invention solves the above-mentioned problems, can be easily obtained industrially by hot melt molding without generating coloring and off-flavor due to thermal decomposition, and the strength and the like inherent to the PVA resin An object of the present invention is to provide a PVA molded article having excellent mechanical properties.
[0009]
[Means for Solving the Problems]
The present invention has been made to solve the problems of the above problems, PVA-based made from resin (A) and hydrazine reduction compound and (B), PVA-based resin 100 weight content of hydrazine of compound A PVA-based molded article obtained by melt-molding a PVA-based resin composition that is 0.05 to 25 parts by weight with respect to parts. The polyvinyl alcohol resin composition preferably contains 0.05 to 20 parts by weight of a plasticizer with respect to 100 parts by weight of the polyvinyl alcohol resin.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
As the PVA resin (A) used in the present invention, those obtained by various known methods are used. For example, a fatty acid vinyl ester obtained by saponifying a fatty acid vinyl ester obtained by a known polymerization method such as a bulk, solution, suspension, or emulsification by a known method is used. Here, examples of the fatty acid vinyl ester used include, but are not limited to, formic acid vinyl ester, propionic acid vinyl ester, and butyric acid vinyl ester. Of these, vinyl acetate is industrially preferred.
[0011]
The degree of saponification of the PVA-based resin is not particularly limited, and is usually 50 to 99.5 mol%, and can be appropriately selected depending on the use of the molded article. Among them, when obtaining a molded article excellent in water resistance, oil resistance and oxygen barrier property, a saponification degree of 98 mol% or more is used, and in obtaining a molded article excellent in water solubility or dispersibility. In general, the saponification degree is 65 to 96 mol%.
[0012]
Although the average degree of polymerization of PVA is not specifically limited, Usually, it is 100-4000, More preferably, it is 300-2500. If the average degree of polymerization is less than 100, the mechanical strength of the resulting molded product tends to decrease, and if it exceeds 4000, the melt viscosity at the time of melting tends to be high and molding tends to be difficult.
[0013]
The PVA resin used in the present invention may be used in combination of two or more kinds of PVA resins.
In addition, the PVA resin used in the present invention may be copolymerized with other copolymerizable monomers as long as the effects of the present invention are not impaired, and a chain transfer agent is used. The polymer terminal may be modified.
[0014]
Examples of monomers copolymerizable with the vinyl acetate include olefins such as ethylene and propylene: polymerizable monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, and isocrotonic acid: maleic acid, fumaric acid, Polymerizable dicarboxylic acids such as itaconic acid: Polymerized dicarboxylic acid anhydrides such as maleic anhydride: Esters and salts of polymerizable monocarboxylic acids and polymerizable dicarboxylic acids: Polymerizable acid amides such as acrylamide and methacrylamide: Acrylic acid Acrylic esters such as methyl, ethyl acrylate and butyl acrylate: Methacrylic esters such as methyl methacrylate, ethyl methacrylate and butyl methacrylate: Vinyl halides such as vinyl chloride and vinyl fluoride: Vinylidene chloride, Halo such as vinylidene fluoride Vinylidene chlorides: Monomers having glycidyl groups such as allyl glycidyl ether and glycidyl methacrylate: methyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl Vinyl ethers such as vinyl ether and stearyl vinyl ether: Nitriles such as acrylonitrile and methacrylonitrile: Allyl compounds such as allyl acetate, allyl chloride, polyoxyethylene allyl ether, polyoxypropylene allyl ether: Vinylsilyl compounds such as vinyltrimethoxysilane, acetic acid Although isopropenyl etc. are mentioned, it is not restricted to this.
[0015]
Examples of the chain transfer agent for modifying the polymer terminal include, but are not limited to, aldehydes and halogen-containing compounds.
[0016]
The PVA resin used in the present invention may be a PVA resin washed with water or methanol in order to remove the alkali metal acetate salt.
[0017]
As the hydrazine compound (B) used in the present invention, various compounds are used. Hydrazine, hydrazine hydrate, hydrazine monohydrate or salt, form hydrazide, acetohydrazide, propionic hydrazide, lauric acid hydrazide, methyl Carbazate, ethyl carbazate, semicarbazide hydrochloride, stearic acid hydrazide, salicylic acid hydrazide, p-hydroxybenzoic acid hydrazide, benzoic acid hydrazide, 1-naphthoic acid hydrazide, carbohydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid Dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanediohydrazide, hexide Decandiohydrazide, terephthalic acid dihydrazide, isophthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 4,4'-bisbenzenedihydrazide, 1,4-cyclohexanedihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, iminodiacetic acid dihydrazide, N, N '-Hexamethylene bissemicarbazide, itaconic acid dihydrazide, ethylenediaminetetraacetic acid tetrahydrazide, citric acid trihydrazide, 1,2,3-benzenetrihydrazide, 1,4,5,8-naphthoic acid tetrahydrazide, nitriloacetic acid trihydrazide, Compounds having a hydrazino group or a hydrazide group in the molecule such as cyclohexanetricarboxylic acid trihydrazide, pyromellitic acid tetrahydrazide, and N-aminopolyacrylamide, and the above The ketone compound is reacted to hydrazine compound, carbohydrazide diacetone hydrazone, may be used hydrazine derivatives, such as adipic acid dihydrazide diacetonehydrrazone it is not limited thereto.
[0018]
Of these, water-soluble hydrazine compounds are preferred from the viewpoint of compatibility with PVA-based resins. Furthermore, adipic acid dihydrazide and carbodihydrazide are preferable.
[0019]
The content of hydrazine of compound (B) of the present invention, with respect to PVA-based resin (A) 100 parts by weight of a 0.05 to 25 parts by weight. Preferably, it is 0.1 to 15 parts by weight.
[0020]
When the content of the hydrazine compound is less than 0.05 parts by weight, the effect of preventing coloring and off-flavor due to thermal decomposition during melt molding is insufficient. On the other hand, if the amount exceeds 25 parts by weight, the effect of preventing coloring and off-flavor due to thermal decomposition will reach its peak, which is disadvantageous in terms of cost.
[0021]
In the present invention, a plasticizer can be further contained. Any plasticizer known as a plasticizer for PVA can be used. Examples thereof include, but are not limited to, polyethylene glycol, glycerin, diglycerin, dibutyl phthalate, dioctyl phthalate, tricresyl phosphate, sorbitol, pentaerythlit, and water.
[0022]
The content of the plasticizer is preferably 0.5 to 20 parts by weight and more preferably 1 to 15 parts by weight with respect to 100 parts by weight of the PVA resin (A). By using a plasticizer, the melt viscosity is lowered, the moldability is improved, and the elongation of the obtained molded body is increased.
[0023]
If the content of the plasticizer is more than 20 parts by weight, the physical properties of the molded product may be adversely affected, and the plasticizer may bleed out, resulting in problems such as deterioration of the appearance of the molded product or stickiness. There is a risk.
[0024]
The PVA resin composition in the present invention can be obtained by mixing a PVA resin and a hydrazine compound. If necessary, in addition to the plasticizer, clay, silica, calcium carbonate, titanium (Ti) compound, nickel ( Various additives such as fillers such as Ni) compounds, colorants, stabilizers, lubricants, antiblocking agents, fragrances, reinforcing fibers, and ultraviolet absorbers can be blended.
[0025]
Furthermore, polymer compounds such as starch, cellulose, polyethylene, polypropylene, polystyrene, polyester, polyamide, and polyurethane can be blended within a range not impairing the effects of the present invention.
[0026]
It can be obtained by mixing PVA resin and hydrazine compound, but there is no particular limitation on the mixing method. The PVA resin and hydrazine compound can be added together and then melt mixed, or PVA plastic such as water can be used. agents for dissolution, or is a hydrazine of compound dispersed can be exemplified a method of absorbing the PVA, not limited to this.
[0027]
The PVA resin composition of the present invention is melt-molded by various known methods. Examples thereof include an extrusion molding method, an injection molding method, a transfer molding method, and a lamination molding method. The extrusion method includes blow molding, inflation molding, co-extrusion molding and the like.
[0028]
The molded product obtained by the present invention can be used as a film, a bottle, a sheet, a hose, a tube, a container, a fiber, a foam or the like, and in particular, if a PVA resin having a saponification degree of 98 mol% or more is used, For applications that require oil resistance, fragrance retention, oxygen barrier properties, etc., and for applications that require water-solubility and water dispersibility by using a PVA resin having a saponification degree of 60 to 97 mol%. Useful.
[0029]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
[0030]
Example 1
PVA resin (average polymerization degree of 1000, saponification degree 87.4 mol%) and 100 parts by weight and the hydrazine of 2 parts by weight of adipic acid dihydrazide powder as compound were dry-blended, a further Glycerin 10 parts by weight of a plasticizer After adding and mixing well, glycerin was absorbed in PVA resin at 60 ° C.
[0031]
Using this resin as a raw material, a film having a thickness of 40 μm and a folding width of 13 cm was obtained by melt molding using an inflation film forming machine. The film forming conditions at this time are shown below.

The following evaluation tests were conducted using this film. As shown in Table 1, the test results were sufficiently high in both strength and elongation, and there was no odor or coloring due to thermal decomposition.
[0032]
Evaluation test 1. Film Strength and Elongation The above film was conditioned at 20 ° C. and 65% RH for 24 hours, and then a distance between chucks of 30 mm and a tensile speed of 50 mm / min was used using Toyo Seiki Co., Ltd. Strograph R3 type. The strength and elongation when the film broke under the conditions were measured.
2. Yellowing Resistance The yellowness (YI) of transmitted light was measured using a spectroscopic color difference meter COH-300A manufactured by Nippon Denshoku Industries Co., Ltd., and the yellowing resistance was evaluated according to the following criteria.
A: YI = less than 1.0 B: YI = less than 1.0 to 3.0 Δ: YI = 3.0 to 10.0
X: YI = 10.0 is exceeded Odor The odor of the film was evaluated according to the following criteria.
A: The smell is not felt at all.
○: Almost no smell is felt.
(Triangle | delta): The decomposition odor of PVA is felt.
X: Vigorous decomposition odor of PVA.
4). Comprehensive evaluation Each of the above evaluations was comprehensively evaluated according to the following criteria.
(Double-circle): There is no coloring by thermal decomposition and generation | occurrence | production of the bad smell by decomposition gas, and the strength and elongation of a film are both high.
○: Coloring due to thermal decomposition and generation of off-flavor due to decomposition gas hardly occur, and both strength and elongation of the film are high.
X: One or more performances are inferior among coloring by thermal decomposition and generation of off-flavor due to decomposition gas, film strength, and elongation.
[0033]
Example 2
A film was obtained in the same manner as in Example 1 except that the blending amount of adipic acid dihydrazide was changed to 7 parts by weight. An evaluation test was performed in the same manner as in Example 1 using this film. As shown in Table 1, the strength and elongation were sufficiently high as shown in Table 1, and there was no odor or coloring due to thermal decomposition.
[0034]
Example 3
A film was obtained in the same manner as in Example 1 except that the blending amount of adipic acid dihydrazide was changed to 0.3 parts by weight. An evaluation test was performed in the same manner as in Example 1 using this film. As shown in Table 1, the strength and elongation were sufficiently high as shown in Table 1, and there was no odor or coloring due to thermal decomposition.
[0035]
Example 4
Except that the hydrazine of compound was changed to sebacic acid dihydrazide, to obtain a film in the same manner as in Example 1. An evaluation test was performed in the same manner as in Example 1 using this film. As shown in Table 1, the strength and elongation were sufficiently high as shown in Table 1, and there was no odor or coloring due to thermal decomposition.
[0036]
Example 5
A film was obtained under the same conditions as in Example 1 except that the PVA resin was changed to one having an average polymerization degree of 600 and a saponification degree of 98.4 mol%, and the film forming conditions were changed to those shown below.
Using this film, an evaluation test was conducted in the same manner as in Example 1. As shown in Table 1, the strength and elongation were sufficiently high as shown in Table 1, and there was no odor or coloring due to thermal decomposition.

Using this film, an evaluation test was conducted in the same manner as in Example 1. As shown in Table 1, the test results were sufficiently high in both strength and elongation, and there was no odor or coloring due to thermal decomposition.
[0037]
Example 6
PVA resin and adipic acid dihydrazide powder 4 parts by weight of the (average polymerization degree of 1000, saponification degree 87.4 mol%) 100 parts by weight of hydrazine of compound by dry blending. This PVA resin composition was melt-molded using an inflation film forming machine to obtain a film having a thickness of 40 μm and a folding width of 13 cm. The film forming conditions at this time are shown below.
[0038]
Example 7
A film was obtained under the same conditions as in Example 6 except that the PVA resin was changed to one having an average polymerization degree of 600 and a saponification degree of 98.4 mol%, and the film forming conditions were changed to those shown below.
Using this film, an evaluation test was conducted in the same manner as in Example 1. As shown in Table 1, the strength and elongation were sufficiently high as shown in Table 1, and there was no odor or coloring due to thermal decomposition.
(Film forming conditions)
Cylinder temperature: 235 ° C
Die temperature: 225 ° C
Screw rotation speed: 30rpm
Discharge rate: 15 g / min
[0039]
Comparative Example 1
Except for adding no hydrazine of compound it is to form a film in the same manner as in Example 1. Using this film, an evaluation test was conducted in the same manner as in Example 1. As a result, as shown in Table 1, the film had intense coloring due to thermal decomposition and generation of intense odor due to decomposition gas.
[0040]
Comparative Example 2
A film was prepared in the same manner as in Example 1 except that the blending amount of adipic acid dihydrazide was changed to 0.01 parts by weight. Using this film, an evaluation test was conducted in the same manner as in Example 1. As a result, as shown in Table 1, the effect of preventing decomposition was not sufficient, and the film had coloring due to thermal decomposition and generation of a strange odor due to decomposition gas.
[0041]
Comparative Example 3
Except for adding no hydrazine of compound created a film in the same manner as in Example 5. The PVA was severely decomposed during molding, and a film could not be obtained.
[0042]
Comparative Example 4
Except for adding no hydrazine of compound it is to form a film in the same manner as in Example 6. Using this film, an evaluation test was conducted in the same manner as in Example 1. As a result, as shown in Table 1, the film had coloring due to thermal decomposition and generation of off-flavor due to decomposition gas.
[0043]
[Table 1]

[0044]
【The invention's effect】
According to the present invention, a PVA molded article having excellent mechanical properties such as strength inherent in PVA can be easily obtained industrially by hot melt molding without causing coloring and off-flavor due to thermal decomposition. .

Claims (1)

Polyvinyl alcohol resin (A) having an average degree of polymerization of 300 to 2500 , 0.3 to 15 parts by weight of hydrazine compound (B), and 100 parts by weight of polyvinyl alcohol resin relative to 100 parts by weight of polyvinyl alcohol resin. 20 1 to 20 parts by weight of process by mixing a plasticizer to obtain a polyvinyl alcohol-based resin composition, and process of inflation molding, characterized in that it comprises a method for producing a polyvinyl alcohol moldings respect.