JP3029483B2 - Highly crystalline polypropylene biaxially stretched film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly crystalline polypropylene biaxially stretched film having excellent rigidity and heat shrink resistance and good antistatic properties.

2. Description of the Related Art Biaxially oriented polypropylene films are used in a wide range of fields such as food packaging, clothing packaging, and industrial applications because of their excellent mechanical properties and transparency. However, with the recent increase in the speed of secondary processing steps such as printing, laminating, and packaging, the rigidity and heat shrink resistance of conventional biaxially stretched polypropylene films have become unsatisfactory. Use of highly crystalline polypropylene has been studied as a method for improving the rigidity and heat shrink resistance of a biaxially oriented polypropylene film.

[0002]

The biaxially stretched film using highly crystalline polypropylene has been improved in rigidity and heat shrinkage resistance due to advanced molecular orientation and crystallization, but has been used in the past. The antistatic effect is insufficient even when the antistatic agent is blended, poor transfer of printing ink,
A problem related to the generation of static electricity in the secondary processing step such as adhesion of dust has occurred, and solving this problem is a new problem.

[0003]

The present invention has been made as a result of intensive studies on imparting an antistatic property to a biaxially stretched film using a highly crystalline polypropylene. The inventor has found that the intended purpose can be achieved by blending the compound B and the bisamide compound, thereby completing the present invention. That is, the present invention relates to a high-crystalline polypropylene having a relation between the melt flow rate (MFR) and the isotactic pentad fraction (P) satisfying 1.00 ≧ P ≧ 0.0151 logMFR + 0.955 (formula 1). , General formula

Embedded image (Where R in the formula is an alkyl or alkenyl group having 12 to 22 carbon atoms) (hereinafter sometimes abbreviated as compound A)
0.05 to 0.20% by weight and 1 mole of an alkyl (or alkenyl) amine represented by the general formula R ₁ NH ₂ (wherein R ₁ is an alkyl group or alkenyl group having 12 to 22 carbon atoms) and ethylene oxide Compound obtained by reacting polyoxyethylene alkyl (or polyoxyethylene alkenyl) amine obtained by adding 2 to 3 moles with at least one selected from higher fatty acids having 12 to 22 carbon atoms (Hereinafter sometimes abbreviated as Compound B) 0.
5 to 1.5% by weight and bisamide compound 0.01 to 0.2% by weight
And a highly crystalline polypropylene biaxially stretched film characterized by the combination of

[0004] Here, the MFR is JIS K 7210.
Is the melt flow index of polypropylene measured under Condition 14 (230 ° C., 2.14 kgf). P means A. Zambelli
Macromolecules Vol. 6, No. 6, 925-926 (197
3), that is, isotactic linkage in pentad units in a polypropylene molecular chain measured using ¹³ C-NMR, in other words, five propylene monomer units are consecutively meso-bonded. The fraction of propylene monomer units at the center of the chain. However,
Assignment of the ¹³ C-NMR spectrum is based on Macromolecules V
ol. 8, No. 5, 687 to 689 (1975). Incidentally, in the measurement of P in the examples described later, using an FT-NMR device of 270 MHZ, 27,000 times of integrated measurement,
The signal detection limit was increased to 0.001 by P.

The highly crystalline polypropylene used in the present invention is a highly crystalline polypropylene in which the relationship between P and MFR satisfies 1.00 ≧ P ≧ 0.0151 log MFR + 0.955 (formula 1). There is no particular limitation on the MFR of this highly crystalline polypropylene, 0.1 to 10 g usually used for polypropylene biaxially stretched film
Those having a range of / 10 min are preferably used. The requirement of the relationship between P and MFR (Equation 1) imposes a lower limit on the P corresponding to the MFR of the highly crystalline polypropylene to be used, since polypropylene having a low MFR generally also has a reduced P. Also, since P is a fraction, the upper limit is 1.
It becomes 00. Such a highly crystalline polypropylene can be produced by the method described in JP-A-58-104907. That is, a reaction product of an organoaluminum compound (I) (eg, triethylaluminum, diethylaluminum monochloride, etc.) or an organoaluminum compound (I) and an electron donor (eg, diisoamyl ether, ethylene glycol monomethyl ether, etc.) VI) with a solid product (II) obtained by reacting with titanium tetrachloride, and further reacting with an electron donor and an electron acceptor (eg, anhydrous aluminum chloride, titanium tetrachloride, vanadium tetrachloride, etc.). The solid product (III) to be obtained is treated with an organoaluminum compound (IV) (eg, triethylaluminum, diethylaluminum monochloride, etc.) and an aromatic carboxylic acid ester (V) (eg, ethyl benzoate, p-methyltoluate, p- (V) and ( It can be obtained by polymerizing propylene in one or more steps in the presence of a catalyst having a molar ratio to III) of V / III = 0.1 to 10/0. One step in this case means one section of continuous or temporary supply of the monomer.

In the present invention, the above P and MF
As long as the relationship with R is satisfied, other polyolefins can be mixed with the above-mentioned highly crystalline polypropylene. Other polyolefins include propylene homopolymer, propylene as a main component, ethylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1,
Crystalline random copolymer or crystalline block copolymer having one or more α-olefins such as octene-1 as a copolymer component, ultra-low density polyethylene, low density polyethylene, linear low density polyethylene, medium Polyethylene such as high density polyethylene, high density polyethylene, polyolefin such as polybutene, poly-4-methylpentene-1, ethylene-propylene copolymer rubber, ethylene
Synthetic rubbers such as propylene / non-conjugated diene copolymer rubber can be exemplified.

Examples of the compound (A) used in the present invention include tallow diethanolamine, stearyl diethanolamine, oleyl diethanolamine, behenyl diethanolamine, palmityl diethanolamine and the like, and are added in an amount of 0.05 to 0.20% by weight based on the high crystalline polypropylene. If the compounding amount of the compound (A) is less than 0.05% by weight, the antistatic effect after film formation is extremely slow and cannot be put to practical use, and if it exceeds 0.20% by weight, the surface of the biaxially stretched film becomes tacky ( (Blocking is likely to occur.)

The compound (B) used in the present invention is an alkyl (or alkenyl) amine represented by the general formula R ₁ NH ₂ (where R ₁ is an alkyl or alkenyl group having 12 to 22 carbon atoms). Reaction of polyoxyethylene alkyl (or polyoxyethylene alkenyl) amine obtained by adding 2-3 moles of ethylene oxide to 1 mole with at least one selected from higher fatty acids having 12 to 22 carbon atoms Unreacted polyoxyethylene alkyl (or polyoxyethylene alkenyl) amine, polyoxyethylene alkyl (or polyoxyethylene alkenyl) amine monofatty acid ester, polyoxyethylene alkyl (or polyoxy Ethylene alkenyl)
It is estimated to be a mixture of amine difatty acid esters. The compounding amount of the compound (B) with respect to the high crystalline polypropylene is 0.5 to 1.5% by weight. If the amount is less than 0.5% by weight, a sufficient antistatic property cannot be obtained. If the amount exceeds 1.5% by weight, the bleeding of the compound (B) becomes remarkable on the surface of the biaxially stretched film, and the transparency of the film and the printing It is not preferable because the suitability and the suitability for lamination are impaired.

The bisamide compounds used in the present invention include methylene bisstearic acid amide, ethylene bisstearic acid amide, hexamethylene bisstearic acid amide, N, N'distearyl adipate amide,
Examples thereof include ethylene bisoleic acid amide and ethylene bis lauric acid amide. The amount is 0.01 to 0.2% by weight based on the high crystalline polypropylene. If the amount of the bisamide compound is less than 0.01% by weight, the antistatic effect after film formation is extremely slow and cannot be put to practical use.
If the content is more than 10% by weight, bleeding of the bisamide compound becomes remarkable on the surface of the biaxially stretched film.

The highly crystalline polypropylene used in the present invention includes, in addition to the above three compounds, ordinary crystalline polypropylenes such as antioxidants, light stabilizers, nucleating agents, lubricants, antiblocking agents and neutralizing agents. Can be used in combination within a range that does not impair the purpose of the present invention.

In the present invention, the highly crystalline polypropylene and the above three compounds and other additives are mixed by a known mixing device (method) such as a ribbon blender, a Henschel mixer (trade name) or a kneading extruder. Then, the obtained composition is formed into a biaxially stretched film by a known method such as a sequential biaxial stretching method by a T-die tenter method or a simultaneous biaxial stretching method by a tubular method. The highly crystalline polypropylene biaxially stretched film thus obtained is, like the conventional polypropylene biaxially stretched film,
It is used after corona discharge treatment to improve printability and metal deposition property.

[0012]

EXAMPLES The present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, the measuring method of the film physical property used in each example is shown below. Young's modulus: under ASTM D 882. A film having a higher Young's modulus is a film having higher rigidity, which is preferable. Heat shrinkage: Length (L ₀ ) 2 in the measurement direction for each of MD and TD
A sample piece having a width of 0 cm and a width of 1 cm was cut out and heated in an oven at 140 ° C. for 15 minutes, then the length (L ₁ ) cm was measured, and the heat shrinkage (S%) was obtained by the following equation. S = 100 × (L ₀ −
L ₁ ) / L ₀ band voltage decay rate: A static honest meter (manufactured by Shishido Shokai Co., Ltd.) was used. The film, which had been conditioned for one day under conditions of 40 ° C.-60% RH, was discharged from the electrode set at a position of 20 mm at a discharge voltage of 10 kv to charge the film. After the charged voltage reached saturation, the discharge was stopped. The decay rate (R%) was obtained from the remaining charged voltage (C) after 2 seconds and the saturated charged voltage (C _S ) by the following equation. _{R = 100 × (C S -C} ) / C S blooming index: 40 Haze value immediately after production of the film from the haze value (H) of ℃ was adjusted 7 days state under conditions of over 60% RH film (H _o) Minus the value. The haze value was measured according to ASTM D 1003. Blocking degree: 40 ℃ -50% R after corona discharge treatment
7cm length from film conditioned for 7 days under H condition,
A 2 cm wide specimen is cut. The ends of the two sample pieces are overlapped by 2 cm so that the corona discharge treated surfaces are in contact with each other, and a weight having a square bottom of 2 cm and a weight of 1 kg is placed on the overlapped portion. In this state, after leaving in a constant temperature bath at 40 ° C. for 24 hours, the force required for shearing and peeling of the overlapped portion (kg / 4c
m ² ) was measured using a tensile tester at a grip distance of 50 mm and a tensile speed of 50 mm / min.

Examples 1-3, Comparative Examples 1-7 2,6-di-t-butyl-p-cresol 0.1% by weight, tetrakis [methyl
ene (3,5-di-t-butyl-4-hydroxy-hydrocinnamate)] metha
ne 0.03% by weight, 0.05% by weight of calcium stearate and 0.10% by weight of silica having an average particle size of 2.0 μm were added.
Compound A, a reaction product of 1 mol of stearyl diethanolamine and 1 mol of stearic acid as a compound A, and ethylene bisstearic acid amide as a bisamide compound were added to highly crystalline polypropylene having a P of 0.965 and a compound A of 2.5. They were blended at the ratios shown in Table 1 and mixed and granulated by a melt kneader. Each of these compositions was melt-extruded by a T-die method at a resin temperature of 240 ° C. and a cooling roll temperature of 40 ° C.
Sheet was obtained. Then, using a pantograph-type biaxial stretching tester, these sheets were preheated at 158 ° C for 100 seconds,
The stretching speed was 10 m / min in each case, and the film was sequentially stretched 4.2 times in the longitudinal direction and 8.2 times in the transverse direction to obtain a biaxially stretched film having a thickness of 25 μm. After subjecting one side of these films to corona discharge treatment, the Young's modulus, heat shrinkage, charged voltage decay rate, blooming index and blocking degree were measured.
Table 2 shows the measurement results.

Example 4 0.1% by weight of 2,6-di-t-butyl-p-cresol, tetrakis [methyl
ene (3,5-di-t-butyl-4-hydroxy-hydrocinnamate)] metha
ne 0.03% by weight, 0.05% by weight of calcium stearate and 0.10% by weight of silica having an average particle size of 2.0 μm were added.
In 3.4, a highly crystalline polypropylene having a P of 0.972, 0.10% by weight of tallow diethanolamine as compound A, compound B
Of 1 mol of polyoxyethylene stearylamine obtained by the addition reaction of 1 mol of stearylamine and 2.5 mol of ethylene oxide, and 1.2 mol of a mixed fatty acid of 20% by weight of palmitic acid and 80% by weight of stearic acid. 0.8% by weight of the compound obtained by the esterification reaction and 0.02% by weight of ethylenebislaurate amide as a bisamide compound were blended and mixed and granulated by a melt kneader.
This composition was melt-extruded by a T-die method at a resin temperature of 240 ° C. and a cooling roll temperature of 40 ° C. to obtain a sheet having a thickness of 1 mm. Then, using a pantograph-type biaxial stretching tester, this sheet was preheated at 158 ° C for 100 seconds, and the stretching speed was 10 m / min, 4.2 times in the longitudinal direction and 8.2 times in the horizontal direction, and the thickness was sequentially increased. A biaxially stretched film having a thickness of 25 μm was obtained. After subjecting one side of the film to a corona discharge treatment, the Young's modulus, heat shrinkage, charged voltage decay rate, blooming index, and blocking degree were measured. Second measurement result
It is shown in the table.

Comparative Example 8 0.1% by weight of 2,6-di-t-butyl-p-cresol, tetrakis [methyl
ene (3,5-di-t-butyl-4-hydroxy-hydrocinnamate)] metha
ne 0.03% by weight, 0.05% by weight of calcium stearate and 0.10% by weight of silica having an average particle size of 2.0 μm were added.
Compound B obtained by subjecting 1 mol of stearyldiethanolamine and 1 mol of stearic acid to esterification reaction with highly crystalline polypropylene having a P of 0.972 and compound B in 3.4.
1.0% by weight was blended and mixed and granulated by a melt kneader. This composition was melt-extruded by a T-die method at a resin temperature of 240 ° C. and a cooling roll temperature of 40 ° C. to obtain a sheet having a thickness of 1 mm. Next, using a pantograph-type biaxial stretching tester, the sheet was preheated at 158 ° C for 100 seconds, and the stretching speed was
At 10 m / min, the film was sequentially stretched 4.2 times in the longitudinal direction and 8.2 times in the transverse direction to obtain a biaxially stretched film having a thickness of 25 μm. After subjecting one side of the film to a corona discharge treatment, the Young's modulus, heat shrinkage, charged voltage decay rate, blooming index, and blocking degree were measured. Table 2 shows the measurement results.

Example 5 0.1% by weight of 2,6-di-t-butyl-p-cresol, tetrakis [methyl
ene (3,5-di-t-butyl-4-hydroxy-hydrocinnamate)] metha
ne 0.03% by weight, 0.05% by weight of calcium stearate and 0.10% by weight of silica having an average particle size of 2.0 μm were added.
In 2.4, a highly crystalline polypropylene having a P of 0.985, compound A was prepared by subjecting 0.12% by weight of lauryl diethanolamine as compound A, compound B by 1.2% by weight of a compound obtained by subjecting 1 mole of stearyl diethanolamine and 1 mole of palmitic acid to an esterification reaction, and bisamide. 0.05% by weight of ethylene bisstearic acid amide was blended as a compound, and the mixture was granulated by a melt kneader. This composition, the resin temperature 240 ℃,
The sheet was melt-extruded by a T-die method at a cooling roll temperature of 40 ° C. to obtain a sheet having a thickness of 1 mm. Next, using a pantograph-type biaxial stretching tester, the sheet was preheated at 158 ° C. for 100 seconds, and the stretching speed was 10 m / min, and the length was 4.2 mm in the longitudinal direction.
The film was sequentially stretched by a factor of 8.2 times in the transverse direction to obtain a biaxially stretched film having a thickness of 25 μm. After subjecting one side of the film to a corona discharge treatment, the Young's modulus, heat shrinkage, charged voltage decay rate, blooming index, and blocking degree were measured. Table 2 shows the measurement results.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

The biaxially stretched film using highly crystalline polypropylene has a high degree of molecular orientation and crystallization, and as a result, good antistatic properties can be obtained only with the conventionally used antistatic agent represented by compound B. Although no anti-static effect was obtained, the combined use of Compound A and a bisamide compound allowed an excellent anti-static effect to be exhibited in a short time. The highly crystalline polypropylene biaxially stretched film of the present invention is excellent in high-speed mechanical suitability in a printing process, a packaging process, and the like because of high rigidity, and does not generate color misregistration in a multicolor printing process because the heat shrinkage is extremely small. Since it has a good antistatic effect, problems related to static electricity in the secondary processing step, such as poor transfer of printing ink and adhesion of dust, are completely eliminated.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ identification code FI C08K 5:17 5:20) B29K 23:00 B29L 7:00 (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08J 5/18 C08L 23/10-23/12 C08K 5/16-5/20 B29C 55/12-55/16

Claims (1)

(57) [Claims] 1. A biaxially stretched film using highly crystalline polypropylene, which has a melt flow rate (hereinafter referred to as M).
FR may be abbreviated as FR) and the isotactic pentad fraction (hereinafter may be abbreviated as P) may satisfy 1.00 ≧ P ≧ 0.0151 logMFR + 0.955 (formula 1). On the other hand, the general formula (Where R in the formula is an alkyl or alkenyl group having 12 to 22 carbon atoms) (hereinafter sometimes abbreviated as compound A)
0.05 to 0.20% by weight and 1 mole of an alkyl (or alkenyl) amine represented by the general formula R ₁ NH ₂ (wherein R ₁ is an alkyl group or alkenyl group having 12 to 22 carbon atoms) and ethylene oxide Compound obtained by reacting polyoxyethylene alkyl (or polyoxyethylene alkenyl) amine obtained by adding 2 to 3 moles with at least one selected from higher fatty acids having 12 to 22 carbon atoms (Hereinafter sometimes abbreviated as Compound B) 0.
5 to 1.5% by weight and bisamide compound 0.01 to 0.2% by weight
A highly crystalline polypropylene biaxially stretched film, characterized by comprising: