JPH08230014A - Manufacture of easily tearable propylene-based resin nonoriented film - Google Patents

Abstract

PURPOSE: To obtain propylene-based resin nonoriented film, in which its excellent characteristics are not impaired and which also has excellent tearability when it is made into a bag by a method wherein amide-based compound represented by the specified formula is mixed with propylene-based resin having the specified melt flow rate and then formed. CONSTITUTION: 0.01-2 pts.wt. of either one of amide-based compounds represented by the formulae I, II and III is mixed with 100 pts.wt. of propylene-based resin, the melt flow rate defined by JIS K7210 of which is 0.5-30g/10min. The resultant mixture is melted and kneaded at the temperature higher than the melting temperature of amide-based compound to propylene-based resin melt and then cooled down to composition so as to form into film under the condition that its temperature is held within the domain ranging from 170 deg.C to below the melting temperature of the amide-based compound to the propylene-based resin melt and its index of cooling rate is 7 or less. In the formulae, R<1> is saturated or unsaturated aliphatic or aromatic hydrocarbon group having the number of carbon atoms of 1-28, R<2> and R<3> are cycloalkyl group, cycloalkenyl group having the number of carbon atoms of the same as or different from those mentioned above or 3-18 and the group indicated in the formula IV.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a non-stretched propylene-based resin film which is blended with a specific amide compound and has excellent transverse tearability.

[0002]

2. Description of the Related Art Non-stretched polypropylene films are excellent in optical properties such as transparency and glossiness, mechanical properties such as tensile strength, rigidity and impact strength, heat resistance, etc. It is used in a wide range of applications such as food packaging, textile packaging, and others.

[0003]

However, these properties are not sufficiently satisfied depending on the application. Among them, due to the inherent properties of polypropylene unstretched film, it has excellent impact strength, but since the tear strength is higher than required, the film does not tear easily and the opening property is poor when formed into a bag. was there. The present invention is intended to provide a propylene-based resin unstretched film, which does not impair the excellent properties which the propylene-based resin originally has, and also has an excellent opening property when formed into a bag. is there.

[0004]

In view of the above problems of the prior art, the inventors of the present invention have made earnest studies to obtain an unstretched propylene-based resin film having excellent tearability, and as a result, have identified it as a propylene-based resin. It was found that this object can be achieved by blending the amide compound of (3), granulating and molding under specific conditions, and completed the present invention. That is, the present invention is based on the melt flow rate (JIS K721
0) in an amount of 0.01 to at least one of the amide compounds represented by the following general formulas (1) to (3) with respect to 100 parts by weight of the propylene resin having a range of 0.5 to 30 g / 10 minutes. 2 parts by weight were blended, and the mixture was melt-kneaded at a temperature not lower than the melting temperature of the propylene-based resin melt of the amide-based compound and then cooled to form a composition. At a temperature lower than the melting temperature of the propylene-based resin melt in the propylene-based resin melt, and the draft ratio represented by the following mathematical formula (1) is 5 or more,
Further, the present invention provides a method for producing a non-stretched propylene resin film, which is characterized in that the film is formed under the condition that the cooling rate index represented by the following mathematical formula (2) is 7 or less.

[0005]

Embedded image R ² —NHCO—R ¹ —CONH—R ³ (1) R ² —CONH—R ¹ —CONH—R ³ (2) R ² —CONH—R ¹ —NHCO—R ³ (3)

(In the formula, R ¹ represents a saturated or unsaturated aliphatic, alicyclic or aromatic hydrocarbon group having ¹ to 28 carbon atoms, and R ² and R ³ may be the same or different. Represents a cycloalkyl group having 3 to 18 carbon atoms, a cycloalkenyl group, or a group represented by the following general formula (4):

[0007]

[Chemical 4]

R ⁴ and R ⁵ in the formula represent a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, an alkenyl group, a cycloalkenyl group or a phenyl group, and R ⁶ and R 5 ⁷ represents a linear or branched alkylene group having 1 to 4 carbon atoms)

[0009]

(Equation 3)

Where G is the width of the die slit, t is the thickness of the obtained film, ρm is the density of the resin extruded from the die slit, ρf is the density of the film, BUR is the blow-up ratio, but in the case of T-die molding, B is used.
It is represented as UR = 1.

[0011]

[Equation 4]

Where τ: cooling rate index (second) AG: air gap (distance between T die and cooling roll) in the case of T die molding, or distance between die and cooling mandrel in the case of inflation molding (Cm) V ₁ : take-up speed (cm / sec) V ₀ : linear velocity of molten resin at die exit (cm / sec)

The present invention will be described in more detail below. The propylene resin used in the present invention has a melt flow rate of 0.5 to 30 g / 10 minutes, preferably 1 to 20.
a resin in the range of g / 10 minutes, a homopolymer of propylene,
Alternatively, a copolymer containing propylene as a main component can be mentioned. If the melt flow rate is lower than the lower limit, the extrusion moldability of the film will be poor, and if it is higher than the upper limit, the impact strength of the film will be significantly reduced. The melt flow rate is in accordance with JIS K7210, 2
It is a value measured under the condition of a temperature of 30 ° C. and a load of 2.16 kg. Examples of the propylene-based copolymer include other 1-alkenes (ethylene, 1-butene, 1-pentene, 1-hexene, 4
-Methylpentene-1 etc.) (including random and block), propylene / ethylene multi-component copolymer (5-ethylidene-2-norbornene, 5-methylene-2-norbornene or 1,4 -Including hexadiene) and the like.

The propylene-based polymer can be produced by applying a conventionally known production method. The catalyst used in these productions is not particularly limited, and examples thereof include a catalyst system containing a titanium-containing solid catalyst component and an organoaluminum compound as a cocatalyst component. The titanium-containing solid catalyst component is a known carrier-supported catalyst component obtained by contacting a solid magnesium compound, titanium tetrahalide and an electron-donating compound, titanium trichloride or a known titanium trichloride as a main component. It is selected from catalyst components. Further, in addition to the above solid catalyst component and cocatalyst component, a catalyst system using a known electron donating compound as the third component may be used.
In addition to these catalyst systems, metallocene catalysts, so-called Kaminsky catalysts, can also be used.

Further, the polymerization method used for producing the propylene-based polymer includes a slurry polymerization method using a hydrocarbon such as hexane and heptane as a solvent, a bulk polymerization method using a liquid propylene as a solvent, and a gas phase method. Various known methods can be mentioned.

Next, as the amide compound to be added to the propylene resin used in the present invention, the following general formulas (1) to (1)
It is selected from the amide compounds represented by (3).

[0017]

Embedded image R ² —NHCO—R ¹ —CONH—R ³ (1) R ² —CONH—R ¹ —CONH—R ³ (2) R ² —CONH—R ¹ —NHCO—R ³ (3)

(R ¹ represents a saturated or unsaturated aliphatic, alicyclic or aromatic hydrocarbon group having ¹ to 28 carbon atoms,
R ² and R ³ may be the same or different and have ^{3 to 1} carbon atoms.
8 represents a cycloalkyl group, a cycloalkenyl group or a group represented by the following general formula (4):

[0019]

[Chemical 6]

R ⁴ and R ⁵ in the formula represent a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, an alkenyl group, a cycloalkenyl group or a phenyl group, and R ⁶ and R 5 ⁷ represents a linear or branched alkylene group having 1 to 4 carbon atoms. )

The amount ratio of the amide compound is 0.01 to 2 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the propylene resin.
It is mixed in a ratio of about 1.5 parts by weight. If the amount is less than the above range, the effect of easy tearing is hardly seen. On the other hand, if the amount exceeds the above range, no significant difference in effect is observed, which is economically disadvantageous, which is not preferable. However, when the propylene-based resin composition containing a high content of the amide-based compound is used as a material for the masterbatch and the compounding amount of the amide-based compound in the final film-forming composition is within the above range. Is not this limitation. Hydrocarbon group R contained in the above general formulas (1) to (3)
Examples of ¹ are more preferably linear alkyl groups and hydrocarbon groups represented by the following general formula (5).

[0022]

[Chemical 7]

(In the formula, X is --CH _2- , --O--, --SO ₂
-, - S -, - CO- , or -C (CH _{3) 2} - represents a. Further, as R ² and R ³ , more preferable examples include a cycloalkyl group and a substituted product thereof, an aromatic hydrocarbon group and a substituted product thereof. More preferably, a cyclohexyl group, and a 2-methylcyclohexyl group, a 3-methylcyclohexyl group, a 4-methylcyclohexyl group, a 2-ethylcyclohexyl group, a 3-ethylcyclohexyl group,
4-ethylcyclohexyl group, 2-propylcyclohexyl group, 2-isopropylcyclohexyl group, 4-propylcyclohexyl group, 4-isopropylcyclohexyl group, 2-tert-butylcyclohexyl group, 4-n-butylcyclohexyl group, 4-isobutylcyclohexyl group Group, 4-sec-butylcyclohexyl group, 4-tert-butylcyclohexyl group, 4-n-amylcyclohexyl group, 4-isoamylcyclohexyl group, 4-sec-amylcyclohexyl group, 4-tert-amylcyclohexyl group, 4- Hexylcyclohexyl group, 4-heptylcyclohexyl group, 4-octylcyclohexyl group, 4-nonylcyclohexyl group, 4-decylcyclohexyl group,
4-undecylcyclohexyl group, 4-dodecylcyclohexyl group, 4-cyclohexylcyclohexyl group, 4
-Substituted products of a cyclohexyl group such as a phenylcyclohexyl group are exemplified.

Among the amide compounds represented by the above general formula (1), (2) or (3), preferred compounds are exemplified by N, N'-dicyclohexyl-1,4-cyclohexanedicarboxamide, N. , N'-dicyclohexyl terephthalamide, N, N'-dicyclohexyl-2,
6-naphthalene dicarboxamide, N, N'-dicyclohexyl-4,4'-biphenyldicarboxamide, p- (N-cyclohexanecarbonylamino) benzoic acid cyclohexylamide, N, N'-dicyclohexanecarbonyl-p-phenylene Examples thereof include diamine and N, N'-dicyclohexanecarbonyl-1,4-diaminocyclohexane. Also, these amide compounds can be used as a mixture thereof.

When molding the propylene resin unstretched film of the present invention, other compounding agents may be added, if necessary, within a range that does not significantly impair the effects of the present invention. Specific examples of such a compounding agent include an ultraviolet absorber,
Optical brightener, antioxidant, neutralizer, antacid, flame retardant, antistatic agent, lubricant, antiblocking agent, pigment,
Fillers, antibacterial agents, other resins and the like can be mentioned. These compounding agents can be used alone or in combination of two or more kinds.

In the molding of the propylene resin unstretched film of the present invention, first, the amide compound is blended with the propylene resin in the above proportion, and the amide compound is melted at a temperature not lower than the melting temperature of the propylene resin melt. Is melt-kneaded to dissolve the amide compound in a propylene resin melt, and the propylene compound is cooled to prepare a propylene resin composition. Alternatively, in the preparation of the above-mentioned propylene-based resin composition, a propylene-based resin composition prepared by containing an amide-based compound in a high content is used as a masterbatch, and a propylene-based resin prepared separately is blended with the propylene-based resin composition A composition in which the amide compound is uniformly finely dispersed can be prepared by performing melt-kneading again at a temperature lower than the melting temperature of the propylene resin in the melt of the propylene resin. Regarding the blending of the propylene-based resin and the amide-based compound, the amide-based compound may be blended when the propylene-based resin is prepared, or may be blended in a separately prepared propylene-based resin. The mixing ratio of the propylene resin as the raw material resin and the amide compound is the above mixing ratio. Furthermore, the above-mentioned other compounding agents can be added and compounded as necessary.

The melt-kneading is carried out at a temperature equal to or higher than the melting temperature of the amide compound in the propylene resin melt. When the amide compound is melt-kneaded at a temperature lower than the melting temperature of the propylene resin melt, the impact strength of the resulting polypropylene unstretched film is significantly reduced. For the melt-kneading, a single-screw extruder, a twin-screw extruder, a Banbury mixer, a continuous mixer,
It can be carried out by using an ordinary kneader such as a mixing roll or a Brabender plastograph.

The unstretched propylene resin film of the present invention can be obtained by film-forming the above propylene resin composition. The molding can be performed according to a usual film molding method. For example, inflation molding with a circular die, T-die molding method with a T-die, etc. are adopted. With respect to the molding conditions, the molding temperature, that is, the resin temperature is in the range of 170 ° C. to the melting temperature of the amide compound in the propylene resin melt, and the draft ratio represented by the following mathematical formula (1) is 5 or more, preferably Is 5 to 50, more preferably 10 to 4
0 and the cooling rate index shown by the following mathematical expression (2) is 7
Hereafter, it is desirable to carry out under the condition of preferably 6 or less.

[0029]

(Equation 5)

Where: G: width of die slit t: thickness of obtained film ρm: density of resin extruded from die slit ρf: density of film BUR: blow-up ratio, but in case of T die molding, B
It is represented as UR = 1.

[0031]

(Equation 6)

Where τ: cooling rate index (seconds) AG: air gap (distance between T die and cooling roll) in case of T die molding, or distance between die and cooling mandrel in case of inflation molding (Cm) V ₁ : take-up speed (cm / sec) V ₀ : linear velocity of molten resin at die exit (cm / sec)

When the above-mentioned film molding is carried out at a molding temperature (resin temperature) higher than the melting temperature of the amide compound in the propylene resin melt, the transverse tearability of the film is lowered. When the draft ratio is less than 5, the optical property of the film or sheet obtained by molding is deteriorated, and when the draft ratio is more than 50, molding stability is deteriorated, which is not desirable.

In the present invention, the cooling rate index (τ) is set within the range of 7 or less. Cooling rate index (τ)
Represents a residence time (second) until the molten resin is extruded from the die and solidified, and may be controlled to a predetermined value by changing each requirement in the mathematical expression (2). For example, in the case of inflation molding, the distance from the die to the mandrel may be changed, in the case of T die molding, the distance between the T die and the cooling roll may be changed, and in order to change V ₀ and V ₁ , extrusion may be performed. It may be controlled by changing the extrusion rate of the machine and the take-up speed of the take-out device, and a predetermined cooling rate index is set by combining these respective elements. When the cooling rate index (τ) exceeds the upper limit of 7, the optical properties of the film are significantly deteriorated, which is not preferable.

[0035]

EXAMPLES The present invention will be described in more detail below with reference to examples. The evaluation methods of the films made in the examples and comparative examples are as follows. (Film Evaluation Method) (1) Melt Flow Rate (MFR) Measurement was performed according to JIS K-7210 (230 ° C., load 2.16 kg). (2) Haze (Haze) The obtained film was measured with a haze meter in accordance with ASTM D-1003. (3) Impact strength (DDI) In accordance with ASTM D-1709, the obtained film was measured by a dirt drop impact and expressed in energy conversion (measured value x load height) for comparison. (4) Rigidity (1% elastic modulus) The obtained film was sampled in a size of 140 mm × 25 mm (long direction is MD direction, TD direction respectively), and the tensile speed was 10 mm / min. It was calculated by the following mathematical formulas (3) and (4).

[0036]

(Equation 7)

[0037]

(Equation 8)

(5) Tear strength (light load Elmendorf tear strength) The obtained film was sampled according to JIS K7128 (Elmendorf tear method) as shown in FIG.
After mounting the sample, make a measurement by inserting a notch as shown in FIG. 2 (if the tear is oblique, the measured value is invalid). From the measurement result, it was calculated by the following mathematical expression (5).

[0039]

[Equation 9]

Example 1 A propylene homopolymer having a melting temperature of 161.5 ° C. determined by DSC (MFR: 2.
0 g / 10 minutes, 100 parts by weight of 1220FH powder manufactured by Mitsubishi Chemical Corporation, N, N'- as an amide compound
0.2 parts by weight of granular powder of dicyclohexyl-2,6-naphthalenedicarboxamide (manufactured by Shin Nippon Rika Co., Ltd.) was added, and further BHT (2,6-ditertiarybutyl-4-methylphenol) was added to 0.2 parts by weight. A resin composition was produced by adding 1 part by weight and 0.1 part by weight of calcium stearate, melt-kneading at a resin temperature of 300 ° C. using a 50 mmφ extruder, and granulating.

N, N'-dicyclohexyl-2,6
-Naphthalene dicarboxamide was found to dissolve in polypropylene melts at temperatures above 270 ° C. The composition thus obtained was extruded from a T-die having a width of 450 mm at a resin temperature of 250 ° C. using a 40 mmφ extruder and cooled and solidified by a chill roll to produce a film having a thickness of 30 μm. The draft rate was 33 and the cooling rate index was 1.1. With respect to the film thus obtained, the haze and impact strength (D
DI), 1% elastic modulus and tear strength were measured and the results shown in Table 1 were obtained.

Example 2 Propylene resin pellets having a melting temperature of 140.0 ° C. determined by DSC (ethylene propylene random copolymer having an ethylene content of 2.5% by weight, MFR 2.0 g / 10 min, Mitsubishi Chemical) The same procedure as in Example 1 was carried out except that a prototype manufactured by K.K. was used. Table 1 shows the evaluation results of the obtained film.

Comparative Example 1 In Example 1, N, N'-dicyclohexyl-2,6-naphthalene dicarboxamide as an amide compound was not added, and a resin temperature of 205 was used using a 50 mmφ extruder. Example 1 was repeated except that the mixture was melt-kneaded at 0 ° C. and granulated. Table 1 shows the evaluation results of the obtained film.

(Comparative Example 2) The procedure of Example 1 was repeated, except that the 50 mmφ extruder was used in Example 1 to melt and knead the mixture at a resin temperature of 205 ° C. for granulation. Table 1 shows the evaluation results of the obtained film.

(Comparative Example 3) In Example 1, 40 mmφ
The same procedure as in Example 1 was performed, except that a film was formed by a T die at a resin temperature of 300 ° C. using an extruder. Table 1 shows the evaluation results of the obtained film.

(Comparative Example 4) The procedure of Example 1 was repeated, except that the cooling rate index was set to 8.0 seconds. Table 1 shows the evaluation results of the obtained film.

Comparative Example 5 Propylene resin pellets having a melting temperature of 140.0 ° C. determined by DSC (ethylene propylene random copolymer having an ethylene content of 2.5% by weight, MFR 2.0 g / 10 minutes, Example) The same procedure as in Comparative Example 1 was performed except that the same as that used in 2) was used. Table 1 shows the evaluation results of the obtained film.

(Comparative Example 6) In Example 2, 50 mmφ
The procedure of Example 2 was repeated, except that the resin was melt-kneaded at a resin temperature of 205 ° C. and granulated using an extruder. Table 1 shows the evaluation results of the obtained film.

(Example 3, Comparative Examples 7 to 8) The same procedure as in Example 2 was carried out except that the conditions in Table 1 and the film thickness were 100 μm. Table 1 shows the evaluation results of the obtained film.

[0050]

[Table 1]

As can be seen from Table 1, the film granulated and molded as a composition under the conditions defined in the present invention does not particularly decrease impact strength and rigidity (1% elastic modulus) by addition of an amide compound. In addition, the tear strength, particularly the tear strength in the TD direction, is reduced to the same level or less as the tear strength in the MD direction,
The film was satisfactory as an easily tearable film. On the other hand, the film according to the comparative example had poor tearability in the TD direction, and was not practical as an easily tearable film.

[0052]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, an easily tearable propylene which does not impair the excellent properties originally possessed by a propylene resin and has an excellent opening property when formed into a bag. It is possible to provide a non-stretched resin film.

[Brief description of drawings]

FIG. 1 shows how to take a sample for measuring tear strength.

FIG. 2 shows how to insert a notch in a sample for measuring tear strength.

[Explanation of symbols]

 1 Film 2 MD Measurement Sample 3 TD Measurement Sample 4 Notch

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29L 7:00

Claims (3)

[Claims] 1. Melt flow rate (JIS K721
0) in an amount of 0.01 to at least one of the amide compounds represented by the following general formulas (1) to (3) with respect to 100 parts by weight of the propylene resin having a range of 0.5 to 30 g / 10 minutes. 2 parts by weight were blended, and the mixture was melt-kneaded at a temperature not lower than the melting temperature of the propylene-based resin melt of the amide-based compound and then cooled to form a composition. At a temperature lower than the melting temperature of the propylene-based resin melt in the propylene-based resin melt, and the draft ratio represented by the following mathematical formula (1) is 5 or more,
A method for producing a non-stretched propylene-based resin film, characterized in that the film is formed under the condition that the cooling rate index represented by the following mathematical formula (2) is 7 or less: embedded image R ² —NHCO—R ¹ —CONH ^{-R 3 (1) R 2 -CONH} -R 1 -CONH-R 3 (2) R 2 -CONH-R 1 -NHCO-R 3 (3) ( wherein, R ¹ is a saturated 1 to 28 carbon atoms Or an unsaturated aliphatic, alicyclic or aromatic hydrocarbon group, R ² and R ³ may be the same or different, and are a cycloalkyl group having 3 to 18 carbon atoms, a cycloalkenyl group, or Represents a group represented by the general formula (4): In the formula, R ⁴ and R ⁵ are hydrogen atoms and have 1 to 12 carbon atoms.
Represents a linear or branched alkyl group, alkenyl group, cycloalkenyl group or phenyl group of R ⁶ , R ⁷
Represents a linear or branched alkylene group having 1 to 4 carbon atoms) Here, G: width of die slit t: thickness of the obtained film ρm: density of resin extruded from the die slit ρf: density of film BUR: blow-up ratio, but in the case of T die molding, B
It is represented as UR = 1. [Equation 2] Where τ: cooling rate index (seconds) AG: air gap (distance between T die and cooling roll) in the case of T die molding, or distance (cm) between die and cooling mandrel in the case of inflation molding V ₁ : Take-up speed (cm / sec) V ₀ : Linear velocity of molten resin at die exit (cm / sec) 2. Hydrocarbon groups R ² and R ³ of an amide compound
Is a cyclohexyl group, The polypropylene-based resin composition according to claim 1. 3. The polypropylene resin composition according to claim 2, wherein the amide compound is N, N′-dicyclohexyl-2,6-naphthalene dicarboxamide.