JP2001247776A - Resin composition and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition suitable for obtaining a film or sheet excellent in blocking resistance while keeping good anti-fogging properties, and to provide a film or a sheet excellent in blocking resistance and a film for stretch package while keeping good anti-fogging properties. SOLUTION: This resin composition contains (A) an anti-fogging agent composed of the ester of an unsaturated fatty acid and a diglycerol and (B) an anti-fogging agent composed of the ester of a <=13C fatty acid and a diglycerol. In the resin composition, the weight ratio of the anti-fogging agent (A) to the anti-fogging agent (B) is (85:15) to (35:65) and the total amount of the anti- fogging agents (A) and (B) is 0.1-20 wt.% based on whole resin composition. This film or sheet comprises the resin composition. This film for stretch package comprises the resin composition. An olefin polymer resin is suitable as the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a resin composition and its use. More specifically, the present invention relates to a resin composition suitable for a film, a sheet, and a film for stretch packaging, which are required to have antifogging property and blocking resistance, and to use thereof.

[0002]

2. Description of the Related Art The demand for films and sheets made of resin is increasing year by year. Among such films and sheets, it is important that films and sheets used for stretch packaging films of meat, fish and shellfish, vegetables, fruits, and the like have excellent antifogging properties. Glycerin fatty acid esters, sorbitan fatty acid esters and the like have been used alone or in combination as antifogging agents. For example, JP-A-5-222252 discloses the use of a resin composition comprising a specific polyethylene resin and a polyglycerin fatty acid ester.

[0003]

However, it is difficult for these conventional techniques to satisfy both antifogging property and blocking resistance. An object of the present invention is to provide a resin composition suitable for obtaining a film or a sheet having excellent blocking resistance while maintaining good antifogging property, and having excellent blocking resistance while maintaining good antifogging property. To provide a stretched film or sheet and a stretch packaging film.

[0004]

That is, the present invention relates to an antifogging agent (A) which is an ester of an unsaturated fatty acid and diglycerin.
And an antifogging agent (B) which is an ester of a saturated fatty acid having 13 or less carbon atoms and diglycerin, wherein the antifogging agent (A) and the antifogging agent (B) (A) :( B) = 85: 15-35: 65, and the total amount of the anti-fogging agent (A) and the anti-fogging agent (B) is 0.1% of the whole resin composition. About 20% by weight of the resin composition. The present invention also relates to a film or sheet comprising the resin composition, and a stretch packaging film comprising the resin composition. Hereinafter, the present invention will be described in detail.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The resin used in the resin composition of the present invention is not particularly limited, but is preferably a non-halogen resin from the viewpoint of recent global environmental protection. Here, the non-halogen resin is a resin which does not substantially contain a halogen atom, and which does not generate a toxic halogen compound at the time of waste incineration. As the resin used in the resin composition of the present invention, an olefin polymer resin is more preferable. The olefin polymer resin is a resin obtained by polymerizing an olefin, and specific examples include ethylene homopolymer, ethylene-α-olefin copolymer, and ethylene-
Vinyl ester copolymer, ethylene-unsaturated carboxylic acid copolymer, ethylene-unsaturated carboxylic acid ester copolymer, propylene homopolymer, propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-
Ethylene-butene-1 copolymer (random copolymer or block copolymer) and the like.

Examples of the ethylene homopolymer include low-density polyethylene and high-density polyethylene, with low-density polyethylene being preferred. The α-olefin in the ethylene-α-olefin copolymer has 3 to 1 carbon atoms.
Α-olefin of 0 is preferred, and specific examples include propylene, butene-1, hexene-1, octene-1, 4-
Methylpentene-1 and the like. The vinyl ester in the ethylene-vinyl ester copolymer is an ester of vinyl alcohol, and examples thereof include vinyl acetate and vinyl propionate. The unsaturated carboxylic acid in the ethylene-unsaturated carboxylic acid copolymer is a carboxylic acid having a carbon-carbon double bond or a triple bond in a molecule, and examples thereof include acrylic acid and methacrylic acid.
The unsaturated carboxylic acid ester in the ethylene-unsaturated carboxylic acid ester copolymer is an ester of the unsaturated carboxylic acid, and examples thereof include methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate. .

More preferably, the resin used in the resin composition of the present invention is a low-density polyethylene, ethylene-α
At least one ethylene selected from the group consisting of an olefin copolymer and an ethylene copolymer having a content of a repeating unit derived from a vinyl ester, an unsaturated carboxylic acid or an unsaturated carboxylic acid ester of 5 to 40% by weight; It is a polymer resin, and in particular, the following (c1) to (c3)
A resin containing an ethylene-α-olefin copolymer (C) having the following properties is preferred. (C1) The α-olefin has 3 to 12 carbon atoms. (C2) a melt flow rate (MFR) of 0.1 to 50;
g / 10 minutes. (C3) Density (d) is 870 kg / m ³ or more and 940 kg
/ M ^{3 or} less.

Specific examples of the α-olefin having 3 to 12 carbon atoms referred to in the above (c1) include propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, and nonene-1. , Decene-1, dodecene-1,
4-methylpentene-1, 4-methylhexene-1 and the like are exemplified. As the α-olefin, only one kind may be used, or two or more kinds may be used in combination. The content of the repeating unit derived from the α-olefin in the copolymer is usually 40 mol% or less.

The MFR referred to in the above (c2) is JIS K6
922-2: a value measured under the conditions of a load of 2.16 kg and a measurement temperature of 190 ° C. according to the method specified in 1997, preferably 0.5 to 10 g / 10 min, more preferably 1 to 5 g / min. 10 minutes. When the MFR is in the above range, the moldability of a film or sheet is excellent, which is preferable.

The density referred to in the above (c3) is JIS K
6922-2: a value measured by the method specified in 1997, preferably 890 kg / m ³ or more and 930
kg / m less than ^3, more preferably less than 895kg / m ³ or more 925 kg / m ^3. When the density is within the above range, the rigidity is sufficiently high and the handleability is excellent as a stretch packaging film, and the film is easily stretched and suitable for use as a stretch packaging film.

The ethylene-α-olefin copolymer (C) is a single-site catalyst comprising a multi-site catalyst comprising the above-mentioned monomer and comonomer using a conventional solid catalyst component or a transition metal compound such as a metallocene complex. By using a solution polymerization method, a slurry polymerization method, a high pressure ionic polymerization method, or a gas phase polymerization method.

As the ethylene-α-olefin copolymer (C), ethylene-α-olefin copolymers having the following properties (c4) to (c6) are preferable. (C4) Composition distribution variation coefficient Cx obtained by the following equation 1.
Is 0.5 or less. Cx = σ / SCBave. (Equation 1) (where, σ represents the standard deviation of the composition distribution, and SCBave. Is the average value of short-chain branches per 1000C (1/1000).
C). (C5) The weight ratio a (% by weight) of the cold xylene-soluble portion has a relationship represented by the following formula 2. a <4.8 × 10 ⁴ × (0.95-d ÷ 1000) ³ +10 ⁶ × (0.95-d ÷ 1000) ⁴ +1 (Formula 2) (where, a is the weight of the cold xylene-soluble portion. (D) represents the density (kg / m ³ ) of the ethylene-α-olefin copolymer. (C6) The ratio of the components eluted at an elution temperature of 88 ° C. or higher in the composition distribution curve is 10%. % By weight or less.

The composition distribution variation coefficient Cx mentioned here indicates a measure of the composition distribution, and a smaller value indicates a narrower composition distribution. The composition distribution coefficient Cx is disclosed in
It is determined by the method described in JP-A-340045.
The composition distribution variation coefficient Cx is preferably 0.5 or less, more preferably 0.20 to 0.45.

The weight ratio a of the cold xylene-soluble portion referred to herein is a
(% By weight) is the US code of federal regulations,
175.1520 of Food and Drugs Administration
Means the value measured by the method specified in When the weight ratio a of the cold xylene-soluble portion satisfies the above range, the blocking resistance is excellent, which is preferable.

Further, the ethylene-α-olefin copolymer (C) has an elution temperature of 88 in the composition distribution curve.
It is preferable that the proportion of the component eluted at a temperature of not less than 10 ° C. is 10% by weight or less, and it is particularly preferable that the proportion is 5% by weight or less.

The ethylene-α-olefin copolymer (C) which satisfies such more preferable conditions is suitably produced by a single-site catalyst prepared by using a transition metal compound such as a metallocene complex, and particularly, a cyclopentadiene type anion. Ethylene and α- produced in the presence of a catalyst prepared using a transition metal compound having a group having a skeleton
Copolymer with olefin (linear low density polyethylene)
Is preferred. The transition metal compound is a so-called metallocene compounds, usually, the general formula ML _a X _na (wherein, M is a transition metal atom of Group 4 or lanthanide series of the Periodic Table of Elements .L is cyclopentadiene A group having an anion skeleton or a group containing a hetero atom, at least one of which is a group having a cyclopentadiene-type anion skeleton, and a plurality of Ls may be cross-linked to each other;
X is a halogen atom, a hydrogen atom or a carbon atom having 1 to 20 carbon atoms.
Is a hydrocarbon group. n represents the valence of the transition metal atom, and a is an integer satisfying 0 <a ≦ n. ) And can be used alone or in combination of two or more. The catalyst is usually used for such a metallocene-based compound,
Organic aluminum compounds such as alumoxane compounds and / or ionic compounds such as trityl borate and anilinium borate, and / or SiO ₂ , Al ₂ O ₃
And an inorganic carrier such as ethylene, an organic polymer carrier such as an olefin polymer such as ethylene, and a styrene polymer.

As the resin containing the ethylene-α-olefin copolymer (C), the ethylene-α-olefin copolymer (C) itself may be used, or the ethylene-α-olefin copolymer may be used. A composition comprising (C) and another resin may be used. As such another resin, an olefin polymer resin different from the ethylene-α-olefin copolymer (C) is preferable. Specific examples of the olefin polymer resin include the above-described ethylene homopolymer, ethylene-α-olefin copolymer, ethylene-vinyl ester copolymer, ethylene-unsaturated carboxylic acid copolymer, and ethylene-unsaturated. Carboxylic acid ester copolymer, propylene homopolymer, propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-ethylene-butene-1 copolymer (random copolymer or block copolymer), etc. (However, those different from the ethylene-α-olefin copolymer (C)). In the case of such a composition, the ethylene-α
The amount of the ethylene-α-olefin copolymer (C) is preferably 95 to 30% by weight when the total amount of all the other resins used together with the olefin copolymer (C) is 100% by weight. It is.

More preferably, the resin containing the ethylene-α-olefin copolymer (C) is 95 to 30% by weight of the ethylene-α-olefin copolymer (C) and the low density polyethylene (D) is 5 to 30% by weight. 70% by weight (however,
(The sum of (C) and (D) is 100% by weight). When the amount of the low-density polyethylene (D) is within the above range, bubble stability during inflation molding becomes better, and transparency is more excellent, which is preferable. Particularly preferred is a resin composed of 90 to 50% by weight of the ethylene-α-olefin copolymer (C) and 10 to 50% by weight of a low-density polyethylene (D),
Most preferably, the resin is composed of 85 to 60% by weight of the ethylene-α-olefin copolymer (C) and 15 to 40% by weight of the low density polyethylene (D).

The low-density polyethylene (D) is obtained by polymerizing ethylene using a free radical generator such as an organic peroxide or oxygen. The polymerization reaction is
Usually under a polymerization temperature of 130 to 300 ° C, 50 to 300MP
It is carried out under the polymerization pressure of a.

The low-density polyethylene (D) is JIS
K6922-2: MFR measured under the conditions of a load of 2.16 kg and a measurement temperature of 190 ° C. by the method specified in 1997 is preferably 0.1 to 100 g / 10 min.
It is more preferably 0.5 to 50 g / 10 min, still more preferably 1 to 10 g / 10 min.
Those exhibiting 0 to 0.930 kg / m ³ are preferred.

The antifogging agent (A) used in the present invention is an ester of an unsaturated fatty acid and diglycerin, such as diglycerin oleate, diglycerin linoleate, diglycerin linolenate, diglycerin erucate. Examples thereof include esters, and diglycerin oleate is particularly preferable.

The antifogging agent (B) used in the present invention is an ester of a saturated fatty acid having 13 or less carbon atoms and diglycerin, such as diglycerin caproate, diglycerin caprate, and diglycerin caprate. And diglycerin laurate, but diglycerin laurate is particularly preferred.

The antifogging agent (A) used in the present invention.
And the weight ratio of (B) is (A) :( B) = 85: 15
35:65, preferably 80:20 to 50:50
And more preferably 80:20 to 60:40. If the proportion of the anti-fogging agent (A) exceeds 85%, the anti-fogging property may deteriorate, and if it is less than 35%, the blocking resistance may deteriorate, which is not preferable.

In the present invention, the total amount of the antifogging agents (A) and (B) is from 0.1 to 20% by weight, preferably from 0.5 to 10% by weight, based on the whole resin composition. 20
If the content is more than the weight percentage, the film may become sticky and adversely affect the heat sealability and the like. 0.1% by weight
If the amount is smaller than the above, the effect of improving the antifogging property and the sliding property is poor, which is not preferable.

The resin composition of the present invention may contain various additives and fillers such as an antioxidant, a nucleating agent,
An ultraviolet absorber or the like can be included. Furthermore, other resins may be blended and used within a range not to hinder the present invention. For example, a recycled resin generated from a trimming loss or the like, or a petroleum resin or a hydrogenated product thereof for the purpose of improving self-adhesion can be blended.

The method for producing the resin composition of the present invention is not particularly limited, and any known method, for example, a kneader,
Kneaders such as Banbury mixers and rolls, 1 shaft or 2
A method in which the raw material resin is heated and melt-kneaded using a screw extruder or the like and mixed with an anti-fogging agent or the like. Further, the raw resin pellets and the anti-fogging agent may be dry-blended.

Further, the resin composition of the present invention may be used as a single layer when applied to a film or a sheet, or may be used as at least one layer of a product having a plurality of layers.

As a method for producing a film or a sheet using the resin composition of the present invention, it is possible to employ a generally known method such as an inflation method or a T-die method.

In the present invention, the thickness of the film or sheet is not particularly limited and can be arbitrarily selected (note that the film and the sheet are distinguished by the thickness. A relatively thick film is called a sheet. Hereinafter, for simplicity, a film and a sheet are collectively referred to as a film.) The thickness of the film of the present invention is usually in the range of 2 to 1000 μm.

The film of the present invention is particularly suitable as a film for stretch packaging. The stretch packaging film of the present invention preferably has a thickness in the range of 2 to 100 μm.

In the present invention, if the film requires shrinkability, it is preferable that the film is formed and then stretched in at least one direction. Stretching can be uniaxial or biaxial. In the case of uniaxial stretching, for example, a commonly used roll stretching method is preferable. In the case of biaxial stretching, for example, a sequential stretching method in which uniaxial stretching is performed and then biaxial stretching may be performed, or a method of simultaneously biaxial stretching such as tubular stretching may be used.

[0032]

Hereinafter, the present invention will be described based on examples.
The present invention is not limited to these examples unless it goes beyond the gist. First, methods for measuring physical properties in the following examples and comparative examples will be described.

(1) Melting point of antifogging agents (A) and (B) Differential scanning calorimeter (RDC22 manufactured by Seiko Instruments Inc.)
0), a sample of 3 mg was previously prepared at 60 ° C. in a nitrogen atmosphere.
After melting for 5 minutes, the temperature was lowered to -60 ° C at a rate of 5 ° C / min. Thereafter, the temperature was increased at 5 ° C./min, and the peak temperature of the maximum peak of the obtained melting endothermic curve was defined as the melting point. The melting point of indium (In) measured at a heating rate of 5 ° C./min using this measuring instrument was 156.6 ° C.

(2) Anti-fogging property A container containing hot water at 60 ° C. was covered with a film, and placed in a thermostat at 0 ° C. for 3 minutes, and the surface condition of the film was observed.
The case where a water film formed on the surface of the film was not disturbed by water vapor and a good perception was obtained was evaluated as good, and the case where the water film was disturbed and the perception was poor was evaluated as x.

(3) Blocking resistance [g / 10 cm
Width] From the film wound on the paper tube, 10
The sample was peeled off at a width of 300 cm, and 300 mm was drawn using a tensile tester.
The peel strength at the time of peeling at / min was determined. The lower this value, the better the blocking resistance.

(4) Coefficient of variation in composition distribution Cx Column 9, line 1 to 1 of JP-A-6-340045
It was determined by the method described in column 1, second line.

(5) Cold xylene-soluble part a 5 g of a polymer was dissolved in 500 ml of boiling xylene, cooled to room temperature, and then left in a warm bath at 20 ° C. for 4 hours. The amount of the polymer dissolved in the xylene at 20 ° C. was determined, and the value of the percentage based on the amount of the used polymer (5 g) was defined as a.

Example 1 As an ethylene-α-olefin copolymer (C), an ethylene / hexene-1 copolymer (trade name: Sumikasen E FV, manufactured by Sumitomo Chemical Co., Ltd.)
401, MFR (load 2.16 kg, measurement temperature 190
C) = 4 g / 10 min, density = 902 kg / m ³ , Cx =
0.42, cold xylene soluble part a = 6.7% by weight, value on the right side of Formula 2 = 11.6, elution temperature 8 in composition distribution curve
60 parts by weight of low-density polyethylene [manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikasen F200-0, MFR (load: 2.16 kg, measurement temperature: 190 ° C.)] = 2 g / 10 min, density = 923 kg /
m ³ ] 40 parts by weight, and an antifogging agent (A) [diglycerin oleate O-71D manufactured by Riken Vitamin Co., Ltd.]
And 1 part by weight of an antifogging agent (B) [diglycerin laurate ester L-71D manufactured by Riken Vitamin Co., Ltd.] in a weight ratio of 75/25 was added, and the mixture was melt-kneaded with a Banbury mixer. To prepare a resin composition,
0 mm, using a screw L / D = 28 extruder, 170
The resin composition pellets were obtained by kneading at ℃. This resin composition pellet is supplied to an inflation film molding machine manufactured by Tommy Machine Industry Co., Ltd. equipped with an inflation die having a die diameter of 100 mm and a die lip of 0.8 mm, and a die temperature of 200 ° C., a blow ratio of 2.5, and a take-up speed of 1
A film having a thickness of 30 μm was produced by inflation molding at 5 m / min. Table 1 shows various characteristic values of the obtained film.

Comparative Example 1 In Example 1, the blending weight ratio of the antifogging agent (A) to the antifogging agent (B) was changed to 100/0 (that is, the antifogging agent (B) was not used). Except for the above, a film having a thickness of 30 μm was produced in the same manner as in Example 1.
Table 1 shows various characteristic values of the obtained film.

Comparative Example 2 A film having a thickness of 30 μm was prepared in the same manner as in Example 1 except that the weight ratio of the antifogging agent (A) to the antifogging agent (B) was changed to 25/75. Was manufactured. Table 1 shows various characteristic values of the obtained film.

[0041]

[Table 1]

[0042]

As described in detail above, according to the present invention,
A resin composition suitable for obtaining a film excellent in blocking resistance while maintaining good antifogging property, a film or sheet excellent in blocking resistance while maintaining good antifogging property, and stretch packaging A film is provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) C08L 23/04 C08L 23/04 // B29K 23:00 B29K 23:00 B29L 7:00 B29L 7: 00F Term (reference) 3E086 AD17 BA02 BA15 DA03 4F071 AA15 AA15X AA16 AA18 AA20 AA20X AA21 AA21X AA28X AA81 AA88 AC10 AE22 AF56 AH04 BA01 BA09 BB07 BB08 BB09 BC01 4F210 AA04C AA04E A1AB1 BB07 BB08 BB09 BB08 BB08 BB08 BB151 BP021 EH046 EH047 EH076 FD206 FD207 GG02

Claims (7)

[Claims] 1. An antifogging agent (A) which is an ester of an unsaturated fatty acid and diglycerin, and an antifogging agent (B) which is an ester of a saturated fatty acid having 13 or less carbon atoms and diglycerin. A resin composition wherein the weight ratio of the anti-fogging agent (A) to the anti-fogging agent (B) is (A) :( B) = 85: 15 to 3
5:65, wherein the total amount of the antifogging agent (A) and the antifogging agent (B) is 0.1 to 20% by weight of the whole resin composition. 2. The resin according to claim 1, wherein the resin is low-density polyethylene, ethylene-
at least one selected from the group consisting of an α-olefin copolymer and an ethylene copolymer having a content of a repeating unit derived from a vinyl ester, an unsaturated carboxylic acid or an unsaturated carboxylic acid ester of 5 to 40% by weight; The resin composition according to claim 1, which is an ethylene polymer resin. 3. The resin composition according to claim 1, wherein the resin contains an ethylene-α-olefin copolymer (C) having the following properties (c1) to (c3). (C1) The α-olefin has 3 to 12 carbon atoms. (C2) a melt flow rate (MFR) of 0.1 to 50;
g / 10 minutes. (C3) Density (d) is 870 kg / m ³ or more and 940 kg
/ M ^{3 or} less. 4. An ethylene-α-olefin copolymer (C)
Is an ethylene-α-olefin copolymer further having the following properties (c4) to (c6). (C4) Composition distribution variation coefficient Cx obtained by the following equation 1.
Is 0.5 or less. Cx = σ / SCBave. (Equation 1) (where, σ represents the standard deviation of the composition distribution, and SCBave. Is the average value of short-chain branches per 1000C (1/1000).
C). (C5) The weight ratio a (% by weight) of the cold xylene-soluble portion has a relationship represented by the following formula 2. a <4.8 × 10 ⁴ × (0.95-d ÷ 1000) ³ +10 ⁶ × (0.95-d ÷ 1000) ⁴ +1 (Formula 2) (where, a is the weight of the cold xylene-soluble portion. (D) represents the density (kg / m ³ ) of the ethylene-α-olefin copolymer. (C6) The ratio of the components eluted at an elution temperature of 88 ° C. or higher in the composition distribution curve is 10%. % By weight or less. 5. A resin comprising 95 to 30% by weight of ethylene-α-olefin copolymer (C) and 5 to 70% by weight of low-density polyethylene (D) (provided that the sum of (C) and (D) is 5. The resin composition according to claim 3, wherein the resin composition is 100% by weight. 6. A film or sheet comprising the resin composition according to claim 1. 7. A film for stretch packaging, comprising the resin composition according to any one of claims 1 to 5.