JP2931625B2 - Stretch molded product containing voids with antistatic properties - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a void-containing stretch molded article of polypropylene having both excellent opacity and antistatic properties.

[Prior Art] The inventors of the present invention have previously filed a patent application for Japanese Patent Application No. 1-074919 or the like regarding "a stretch molded article of polypropylene having excellent opacity and a production method" using a specific petroleum resin. . However, depending on the application, for example, general packaging materials, decorative materials,
For applications such as printing paper, tracing paper, or labels, there is a problem of reduced product value due to dust adhesion, problems such as scattering of printing ink at the time of printing, and workability due to irregularities at the time of superimposition due to repulsion of static electricity in the film shape. There are problems such as lowering.

That is, when a composition in which a petroleum resin having a specific high softening point is added to crystalline polypropylene is stretched at a temperature lower than the softening point of the petroleum resin, fine voids are generated. But,
Since the void inside the resin and the expression of the antistatic property due to the orientation provided by stretching have not yet reached a satisfactory level, the applications of the void-containing material have been restricted.

[Problems to be Solved by the Invention] In view of such circumstances, the present inventors have conducted various studies to impart antistatic properties. As a result, the total weight parts of the two specific antistatic agents and the combination of the two in the combination use of two specific antistatic agents By selecting the ratio, it was found that a void-containing stretch molded product of polypropylene having both excellent opacity and antistatic property was obtained, and the present invention was achieved.

[Means for Solving the Problems] That is, the present invention provides an antistatic method, wherein the composition comprising the following (i) to (iv) is subjected to the following treatment (v). Cavity-containing stretch molded product: (i) 100 parts by weight of crystalline polypropylene (ii) 3 to 50 parts by weight of a cyclopentadiene-based petroleum resin having a softening point (ring and ball method) of 160 ° C. or higher (Where R is a hydrocarbon group having 16 to 22 carbon atoms; n and m are 1
A higher aliphatic amine derivative represented by the following formula:
A nonionic surfactant of 0.0 to 1 part by weight of a product obtained by an esterification reaction with 22 higher fatty acids, (Where R _{1 is} a hydrocarbon group having 16 to 22 carbon atoms; R ₂ and R ₃ ,
R _4: a lower alkylene group having mutually identical or different; X: -OH, -
CONH ₂ , —COOH or a salt thereof) 0.1 to 1.0 part by weight of a betaine-type amphoteric surfactant wherein the weight ratio of the surfactants (A) and (B) is 8/2 to 2/2 /
8, preferably in the range of 5/4 to 4/5, and (A) +
(B) is a composition in the range of 0.2 to 2.0 parts by weight, (v) the composition is stretched at least twice in at least one direction at a temperature equal to or lower than the softening point of the petroleum resin specified in (ii) above. .

[Material of Molded Product] As the crystalline polypropylene resin used in the present invention, a homopolymer of propylene, ethylene containing propylene as a main component, or at least one kind of other α-olefin having 4 or more carbon atoms is used. Copolymer or a mixture thereof, for example, crystalline homopolymerized polypropylene, crystalline propylene / ethylene block copolymer, crystalline propylene / ethylene random copolymer, crystalline propylene / 1-butene copolymer , Crystalline propylene
-Hexene copolymer, crystalline propylene / ethylene / 1
-Butene terpolymer, crystalline propylene / ethylene /
Examples thereof include 1-hexene terpolymer and mixtures thereof.

These are obtained by performing homo- or copolymerization by a known method such as a slurry polymerization method, a solution polymerization method, and a gas-phase polymerization method using a known stereospecific catalyst such as a Ziegler-Latter catalyst and an application system thereof. I can do it.

Although these crystalline polypropylene resins are well known, in the present invention, they contain a propylene component in an amount of 70% by weight or more, the boiling n-heptane extraction residue is 70% by weight,
Preferably, 80% or more is used.

In addition, speaking of the crystalline melting point showing a high correlation with the stretching temperature, the homopolymer of propylene showing the highest crystalline melting point
Although it is about 160 to 166 ° C., by copolymerizing propylene with one or more kinds of ethylene or α-olefin having 4 or more carbon atoms, it is possible to obtain a copolymer having a crystal melting point lower than that. And low-melting point copolymers having a melting point of around 110 ° C. are also known.

The crystalline polypropylene resin has a melt flow rate (based on JIS K7210 test condition 14.
0.1 to 20 g / 10 min, preferably 0.3 to 10
g / 10min.

[Hydrogenated cyclopentadiene-based petroleum resin] The cyclopentadiene-based petroleum resin used in the present invention is cyclopentadiene, dicyclopentadiene obtained from steam cracking of petroleum naphtha or the like, a polymer thereof, or a mixture thereof (hereinafter, referred to as a mixture thereof). , A cyclopentadiene component) as a main component, and a petroleum resin obtained by polymerization of the fraction. A solvent such as a metal such as palladium, nickel and cobalt or a catalyst such as an oxide thereof is used to form a solvent. Hydrogenated cyclopentadiene-based petroleum resin hydrogenated in the presence or a mixture thereof, containing at least 50% of a cyclopentadiene component and having a softening point of 160 ° C. or more, especially a softening point (ring and ball method) ) 1
Hydrogenated cyclopentadiene-based petroleum resins having a temperature of 70 ° C. or more and an iodine value of 20 or less are preferable. If the softening point is 155 ° C. or less, it is difficult to impart sufficient opacity to the stretch-formed product, and thus it is not suitable for obtaining a stretch-formed product having fine cavities.

A suitable amount (content) of the hydrogenated cyclopentadiene-based petroleum resin in the molding polypropylene resin composition is usually set to 3 to 50 parts by weight, preferably 8 to 40 parts by weight, more preferably 10 to 30 parts by weight. I do.

[Compound of Nonionic Surfactant] The compound (A) of the nonionic surfactant used in the present invention includes a higher aliphatic amine derivative (alkyl) whose main component is represented by the general formula (A-1). Ester of ethylene oxide (2 mol adduct of amine or the like) and a higher fatty acid having 16 to 22 carbon atoms.

(Where R is an aliphatic hydrocarbon group having 16 to 22 carbon atoms; R ₁ and R ₂ are a hydrogen atom or a higher fatty acid-forming acyl group having 16 to 22 carbon atoms, and R ₁ and R ₂ At least one is not a hydrogen atom; n and m are numbers from 1 to 4 which may be the same or different from each other), to produce an ester represented by the general formula (A-1), for example, The higher aliphatic amine derivative represented by the general formula (A-2) is subjected to an esterification reaction (dehydration condensation) with the following higher fatty acid.

(Where R is a hydrocarbon group having 16 to 22 carbon atoms; n and m are 1
The higher aliphatic amine derivatives may be, for example, the following: palmityl diethanolamine,
Ethylene oxide adducts of alkylamines such as stearyldiethanolamine, oleyldiethanolamine, behenyldiethanolamine and erucyldiethanolamine.

[Higher fatty acids] Examples of the higher fatty acids include the following: palmitic acid, stearic acid, oleic acid, behenic acid, erucic acid and the like. Among these, preferred are palmitic acid, stearic acid and oleic acid.

[Breakdown of Esterification Reaction Product] The esterification reaction product as described above is not a single compound, but is obtained as a mixture containing at least three compounds in which R ₁ and R ₂ are different from each other.

For example, a reaction product obtained by mixing equimolar amounts of alkyldiethanolamine and higher fatty acid and reacting at 140 to 180 ° C. for 4 to 10 hours has one of two hydroxyethylene groups of alkyldiethanolamine esterified with higher fatty acid. Fatty acid monoester of alkyldiethanolamine 50-70% by weight, both hydroxyethylene groups are obtained as a mixture of 10-30% by weight of fatty acid diester of alkyldiethanolamine esterified and 5-20% by weight of unreacted alkyldiethanolamine. .

[Betaine-type amphoteric surfactant] The betaine-type amphoteric surfactant used in the present invention is represented by the following general formula (B): (Where R _{1 is} a hydrocarbon group having 16 to 22 carbon atoms, R ₂ ,
R ₃ , R ₄ : mutually the same or different lower alkylene groups, X: -O
H, -CONH _2, -COOH or salts thereof. As an example of a typical compound of the betaine type amphoteric surfactant, the betaine type surfactant is N-stearyl-N, N-
Bis (2-hydroxyethyl) -N-acetoxyamine, N-palmityl-N, N-bis (2-hydroxyethyl) -N-acetoxyamine and N-oleyl-N, N-
At least one member selected from the group consisting of bis (2-hydroxyethyl) -N-acetoxyamine can be used.

Example: N-stearyl-N, N-bis (2-hydroxyethyl) -N-acetoxyamine: [Preparation of Stretched Molded Product] The combined weight ratio of surfactants (A) and (B) added for preparing the stretched molded product of the present invention is from 8/2 to 2/8, preferably 5/4. It is an essential condition for achieving the effect of the present invention that the total amount of (A) + (B) is 0.2 to 2 parts by weight.

If each is used alone, even if it is added as a mixture, if it is out of the combined range, or if it is within the above-mentioned combined range, if the added amount is too small, the cavity-containing stretch having an excellent antistatic effect. A molded product cannot be obtained. For example, the antistatic property of the surfactant (A) is the same as that of the surfactant (B).
Although it is more powerful than the shading, it has the drawback that, in addition to requiring a large amount of addition, it greatly bleeds, especially when it comes into contact with mineral oil.

Conversely, the surfactant (B) has a long-lasting antistatic property, but has a low bleeding property and thus has a long-lasting property.
In any case, the use of a single substance is insufficient to exhibit the expected performance.

However, in the present invention, the cavity-containing stretched polypropylene having excellent opacity and excellent antistatic properties is provided by regulating the combined use of the surfactants (A) and (B), the mutual ratio thereof and the total amount added. It has become possible to obtain molded articles.

According to the formulation of the present invention, the antistatic property improvement width 30
%, Preferably at least 40%, more preferably at least 50%.

In the composition used in the present invention, additives known to be added to polypropylene as necessary, such as processing stabilizers, antioxidants, slip agents, inorganic fillers, ultraviolet absorbers, nucleating agents and various polymers And the like.

Examples of a method for producing a molding composition which is a raw material for forming the cavity-containing stretch molded product of the present invention include a method of mixing the respective components with an ordinary blender or a Henschel mixer (trade name). However, it is usually practical to melt and mix the components mixed by the above means using an extruder, a Banbury mixer, or the like, and use it in the form of a pellet-shaped composition.

The molding composition thus obtained is melt-extruded using an extruder and a die, and the obtained unstretched raw material is subsequently uniaxially or biaxially stretched by a known method to thereby obtain the opacity desired by the present invention. And a polypropylene-containing stretch-formed product excellent in both antistatic property and antistatic property.

As the stretching method, a known uniaxial stretching method such as roll stretching, oven stretching, hot plate stretching, or a known or simultaneous biaxial stretching method such as a tubular stretching (inflation biaxial stretching) method or a tenter stretching method may be used. Although any of the methods can be used, the raw fabric temperature at the time of stretching must be set to be equal to or lower than the softening point of the petroleum resin in the molding composition. Setting these conditions is indispensable for obtaining an opaque stretch molded product having a total light transmittance of 60% or less, preferably 40% or less.

By stretching the composition in at least one direction at least 2 times each and the area magnification at least 4 times, the stretch molded product aimed at by the present invention can be obtained. In biaxial stretching, high-magnification biaxial stretching in which the area ratio of the object to be stretched is about 10 to 60 times, whether simultaneously or sequentially, is particularly preferred.

In addition, even if the molding composition used in the present invention is simply formed into a film, the obtained unstretched molded product remains as a white opaque translucent molded product with a degree of reduced transparency.

The stretch molded product obtained in the present invention may be subjected to a surface treatment such as a corona treatment or a plasma treatment in an atmosphere such as air, oxygen and / or nitrogen, if necessary.

[Examples and Comparative Examples] The present invention will be further described by the following Examples and Comparative Examples, but the present invention is not limited to these Examples.

Here, the evaluation of the characteristic values used in the following examples and comparative examples was performed by the following method.

(1) Softening point (ring and ball method; ° C): compliant with JIS K 2207 (5) MFR (g / 10min): compliant with JIS K 7210-1976 Test condition 14 (230 ° C; 21.2N) (3) Total light transmission Class (%): Conforms to JIS K 6714. (4) Antistatic property: 10 KV is applied to the sample using a measuring instrument (trade name: Static Honest Meter (manufactured by Shishido Shokai)) in an atmosphere of 23 ° C. and 50% relative humidity. The application is stopped when the charged voltage of the sample reaches saturation, and the decay rate (%) of the charged voltage after 30 seconds is expressed.

(5) Oil bleed (%): The gloss before and after the treatment of the sample with ASTM D 523 (angle 20 °) was measured, and the difference between the measured values was determined. The larger the difference, the more bleed.

[Examples 1-3] Crystalline polypropylene [MFR (230 ° C; 21.2N) 2.1g / 10m
in, boiling n-heptane insoluble component content 96%] powder 100
In addition to 0.2 parts by weight of phenolic antioxidant (BHT) and 0.1 part by weight of calcium stearate, hydrogenated cyclopentadiene-based petroleum resin [softening point (ring and ball method)
177 ° C., iodine number 12] was 25 parts by weight in Example 1, 20 parts by weight in Example 2, 10 parts by weight in Example 3, and the specified amounts of nonionic surfactant and betaine compound shown in Table 1. After mixing the whole with a Henschel mixer (trade name), the mixture was melt-mixed at 230 ° C. through an extruder, and the molten mixture was cut after cooling and cut into three types. To obtain a molding composition in the form of pellets.

Each of the obtained molding compositions was melt-extruded at a temperature of 270 ° C. using an extruder having a diameter of 40 mm and a T-die connected to the downstream end thereof, and this extrudate was quenched by a mirror-surface cooling roll maintained at 40 ° C. Thus, three unstretched raw sheets having a thickness of 0.8 mm were obtained.
Next, each of the material sheets is cut into a square, and the cut material is mounted on a Pandagraph-type biaxial stretching machine and stretched four times in the length direction of the material (flow direction of the resin) at a temperature of 155 ° C. , Immediately after stretching it eight times in the direction perpendicular to it,
Heat treatment was performed at the same temperature under tension for 10 seconds to obtain three types of successively biaxially stretched films having a thickness of about 28 μm.

One surface of each of the obtained films was subjected to a corona treatment with a target of a wetting index of 40 dyn / cm, and the antistatic property was measured after being left in a room at 23 ° C. and 50% RH for 7 days. Further, a test piece was prepared by further superimposing the sample on a backing paper in which paper was impregnated with minerals in advance,
The test piece was measured for glossiness after leaving the test piece under a load of 300 g / (15 × 15) cm ² at 40 ° C. for 3 days, and the bleeding state due to oil was observed from the difference from the glossiness immediately after film formation. The total light transmittance of this test piece was measured immediately after film formation, and the results are shown in Table 1.

[Examples 4 and 5] Crystalline polypropylene [MFR (230 ° C; 21.2N) 2.1g / 10m]
in, boiling n-heptane insoluble component content 96%] powder 100
In addition to 0.2 parts by weight of phenolic antioxidant BHT and 0.1 part by weight of calcium stearate, hydrogenated cyclopentazineene-based petroleum resin [softening point (ring and ball method)
177 ° C., iodine value 12] 40 parts by weight in Example 4, 30 parts by weight in Example 5, and a combination of a specified amount of a nonionic surfactant and a betaine compound shown in Table 1 were blended. . After mixing this mixture with a Henschel mixer (trade name), the mixture was passed through an extruder for 230 minutes.
The mixture was melted and mixed at ℃, and cut after cooling to obtain a pellet-shaped composition. The results are shown in Table 1.

[Example 6] Crystalline polypropylene [MFR (230 ° C; 21.2N) 2.0g / 10m]
in, boiling n-heptane insoluble component content 97%] powder 100
0.2 parts by weight of phenolic antioxidant BHT, 0.1 part by weight of calcium stearate, 20 parts by weight of hydrogenated cyclopentadiene-based petroleum resin [softening point (ring and ball method) 163 ° C., iodine value 15] and 1 part by weight A specified amount of a combination system of a nonionic surfactant and a betaine compound shown in the table was blended, and this blend was mixed with a Henschel mixer (trade name).

The mixture was melted and mixed at 240 ° C. through an extruder, and the molten mixture was cut after cooling to obtain a pellet-shaped molding composition. Using this composition, a raw film was produced in accordance with Example 1, and a stretched film was prepared from this film. Table 1 shows the results.

[Example 7] Crystalline polypropylene [MFR (230 ° C; 21.2N) 2.0g / 10m]
in, boiling n-heptane insoluble component content 97%] powder 100
0.2 parts by weight of phenolic antioxidant (BHT), 0.1 parts by weight of calcium stearate, hydrogenated cyclopentadiene-based petroleum resin [softening point (ring and ball method) 168 ° C,
An iodine value 13] was mixed with 15 parts by weight and a specified amount of a combination of a nonionic surfactant and a betaine compound as shown in Table 1. The mixture was mixed with a Henschel mixer (trade name), melt-mixed at 240 ° C. through an extruder, and the molten mixture was cut after cooling to obtain a pellet-shaped molding composition. Using this composition, a raw film was produced in accordance with Example 1, and a stretched film was prepared from this film. The results are shown in Table 1.

[Comparative Examples 1 to 3] Comparative Example 1 in which none of the surfactants (A) and (B) shown in Table 1 was added from the composition of Example 1, Comparative Example 2 in which (B) was not added, and (A) A raw film was produced in accordance with Example 1 except that each molding composition of Comparative Example 2 without addition was used, and each stretched film was prepared from these films. Table 1 shows the results.

Comparative Example 4 A stretched film was produced in the same manner as in Example 1, except that the amount of the hydrogenated cyclopentadiene-based petroleum resin in the molding composition of Example 1 was changed to 1% by weight. Table 1 shows the results.

[Experimental Findings] As is clear from Table 1, the samples of Examples 1 to 7 of the present invention exhibited good opacity, antistatic properties, oil bleed resistance and the like. Example 1
Each sample of No. 3 lacked both antistatic properties and oil bleed resistance, and the sample of Comparative Example 4 lacked opacity, one of the goals of the present invention.

[Effects of the Invention] The antistatic void-containing stretch molded product of the present invention is obtained by adding a specific high softening point petroleum resin to polypropylene, and has excellent antistatic properties and resistance to mineral oil and the like. Because it has oil bleeding properties, it exhibits superior performance compared to conventional decorative materials, general packaging materials, packaging materials, synthetic paper, etc., and also in applications such as fiber packaging and oily foods Because they are useful, they are useful for expanding their demand.

Continuation of the front page (51) Int.Cl. ⁶ identification code FIB29L 7:00 C08L 23:10 (58) Field surveyed (Int.Cl. ⁶ , DB name) C08J 9/00-9/14 B29C 55 / 00-55/30

Claims (4)

(57) [Claims] 1. An antistatic void-containing stretch molded article characterized in that the composition comprising the following (i) to (iv) has been subjected to the following treatment (v): 100 parts by weight of crystalline polypropylene (ii) Cyclopentadiene-based petroleum resin having a softening point (ring and ball method) of 160 ° C. or more and an iodine value of 20 or less 3 to 50 parts by weight (Where R is a hydrocarbon group having 16 to 22 carbon atoms; n and m are 1
A higher aliphatic amine derivative represented by the following formula:
Nonionic surfactant of product obtained by esterification reaction with higher fatty acid of No. 22 0.1 to 1 part by weight (Where R ₁ represents a hydrocarbon group having 16 to 22 carbon atoms,
R ₂ , R ₃ , R ₄ : mutually the same or different lower alkylene group,
X: -OH, -CONH _2, betaine type surfactants represented by representing each -COOH or a salt thereof), the weight ratio of 0.1 to 1 parts by weight, however, the surfactant (A) and (B) 8 / 2〜2 / 8
Wherein (A) + (B) is in the range of 0.2 to 2 parts by weight, and (v) the composition is treated at a temperature equal to or lower than the softening point of the petroleum resin specified in (ii) above. It is stretched at least twice in at least one direction. 2. The stretched molded article containing an antistatic cavity according to claim 1, wherein the cyclopentadiene petroleum resin has a softening point (ring and ball method) of 170 ° C. or more and an iodine value of 20 or less. 3. A higher aliphatic amine derivative having 16 to 16 carbon atoms.
The products obtained by the esterification reaction with 22 higher fatty acids are the esterification reaction product of palmityldiethanolamine and palmitic acid, the esterification reaction product of stearyldiethanolamine and stearic acid, and the ester of oleyldiethanolamine and oleic acid 3. An esterification reaction product of one or more higher alkyl diethanolamines selected from the group formed by an esterification reaction product and a higher fatty acid, according to claim 1 or 2, An antistatic cavity-containing stretch molded product. 4. The method according to claim 1, wherein the betaine type surfactant is N-stearyl-
N, N-bis (2-hydroxyethyl) -N-acetoxyamine, N-palmityl-N, N-bis (2-hydroxyethyl) -N-acetoxyamine and N-oleyl-N,
The charge according to any one of claims 1 to 3, wherein the charge is at least one selected from the group consisting of N-bis (2-hydroxyethyl) -N-acetoxyamine. Prevented cavity-containing stretch molded products.