JP2000072938A - Polyolefin resin composition, its sheet and its molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyolefin resin composition that has rigidity, heat resistance, transparency, impact resistance and thermoformability possessed by polypropylene at a high level in a well-balanced combination. SOLUTION: A polyolefin resin composition comprises (A) 50-85 wt.% crystalline polypropylene which may include α-olefin as a comonomer, wherein the component A has a) MFR of 0.1-50 g/10 min, and b) a main melting peak temperature on a DSC curve of not less than 160 deg.C, a crystallization initiation temperature of not less than 130 deg.C and a crystallization peak temperature of not less than 125 deg.C, (B) 15-50 wt.% copolymer of ethylene as a main component and α-olefin, wherein the component B has c) a density of 0.93-0.88 g/cm3, d) MFR of 0.1-50 g/10 min and satisfies e) a relationship of H/W>=2.33×10-3( deg.C-1) when a maximum peak temperature on an elution curve obtained by temperature rising elution fractionation is 15-85 deg.C, H represents the height of the peak (a unit: fraction) and W represents the width of the peak at one third of the height H (a unit: deg.C), and (C) 0.03-2 wt.% nucleating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin-based resin composition containing polypropylene as a main component, a sheet and a molded product used for packaging materials, stationery and other industrial materials. In particular, rigidity, impact resistance, heat resistance,
The present invention relates to an excellent polypropylene-based sheet having high levels of transparency and thermoformability.

[0002]

2. Description of the Related Art Polypropylene sheets are inexpensive and have excellent rigidity and heat resistance, and are therefore used in a wide range of fields such as packaging materials, stationery and other industrial materials. Polypropylene resins have the drawback of inherently inferior transparency.However, in the case of propylene homopolymers and crystalline random copolymers with ethylene, quenching molding and the addition of an appropriate nucleating agent can significantly improve the properties. This allows it to be used for a wider variety of applications.

However, homopolymers of propylene and crystalline random copolymers with ethylene have the drawback of poor impact resistance. In order to improve this, when a general polyethylene or olefin rubber is blended. However, at this time, the transparency is greatly reduced, and the method described above is not sufficiently improved. Further, when attempting to impart impact resistance that can withstand use in frozen food packaging or cold regions, such a method requires a considerable amount of compounding, resulting in a decrease in rigidity. on the other hand,
There is a so-called block copolymer (impact copolymer) in which a polyethylene component or an amorphous or low-crystalline propylene-ethylene copolymer is dispersed in crystalline polypropylene by copolymerization with ethylene. Is extremely poor in transparency, and the transparency cannot be improved even by the method described above. That is, it has been difficult for conventional polypropylene-based sheets to achieve high levels of transparency, rigidity, and impact resistance.

[0004] Further, polypropylene-based sheets are often formed into a shape having irregularities by secondary processing generally called thermoforming and used for containers and the like.
Since the sheet is heated and processed to a molten state, a sheet with less elongation or sagging due to its own weight is easier to handle, and is excellent in yield and productivity. Therefore, as polypropylene, a material having a higher melt viscosity is more suitable, but there is a limit in practical use, and polyethylene is often blended to make up for this.
In this case, transparency is greatly deteriorated as described above. Further, although the transparency of the sheet is good, the transparency may be significantly deteriorated through the thermoforming process. Therefore, it is not sufficient that the sheet is transparent only.

[0005]

In recent years, the range of use has been broadened as represented by the increase in cooked foods which are directly heated from the frozen state and eaten, and the tapaware and costume cases have been made more transparent. The functions required of materials have been broadened and enhanced, such as the need for safety due to the enforcement of the PL law.
Diversified, even for polypropylene-based sheets,
In order to satisfy these requirements, further improvement in performance is required. Of the properties of polypropylene that have limitations alone, such as rigidity, heat resistance, transparency, impact resistance, and thermoformability, only a limited number can be improved by conventional technology, and all of these can be improved. At the same time, there was no technology to achieve a high level of compatibility, so there was a limit to meeting the needs described above.

[0006] The present invention relates to a polypropylene-based sheet which has been difficult to achieve compatibility with the prior art.
Combines high levels of transparency, impact resistance, and thermoformability, and is used in a very wide range of applications by achieving an extremely high level of impact resistance enough to withstand use in frozen food packaging and cold regions. An object of the present invention is to provide an excellent polypropylene-based sheet, a polyolefin-based resin composition as a sheet material, and an excellent thermoformed product obtained from the sheet.

[0007]

Means for Solving the Problems The present invention uses the specific polypropylene resin and the polyethylene resin, and further uses a nucleating agent capable of improving transparency, rigidity and heat resistance in combination with the nucleating agent. To solve the above problem. Specifically, for a polypropylene resin having a certain degree of crystallinity and a specific range of MFR, transparency, rigidity and heat resistance are improved by adding a nucleating agent, and furthermore, a certain temperature rise elution fractionation property and density, MFR
The purpose of the present invention is to solve the above-mentioned problems by improving the impact resistance and the thermoformability by blending an appropriate amount of a polyethylene resin having the following.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. 1. Component (A) Polypropylene Resin The component (A) is a crystalline polypropylene which may contain an α-olefin having 2 to 20 carbon atoms other than propylene as a comonomer, and has predetermined characteristics. Specifically, it is a propylene homopolymer (A1) or a copolymer (A2) of propylene and an α-olefin having 2 or 4 to 20 carbon atoms containing propylene as a main component, and has an MFR (JIS-K6758: temperature of 230). ° C, load 2.16 kgf) is 0.1 to 50 g / 10 min, and the main melting peak temperature of this component (A) on the curve obtained by DSC (JIS-K7121) is 160
° C or higher, and the crystallization start temperature of this component on the DSC curve is 130 ° C or higher, and the crystallization peak temperature is 125 ° C.
Those that are above are selected.

Further, as long as the properties after mixing are within the above-mentioned ranges, a mixture of two or more crystalline polypropylenes corresponding to (A1) or (A2) may be used. It may be. One or more α-olefins as the comonomer (A2) can be used, and examples thereof include ethylene, 1-butene, 1-pentene, and 1-pentene.
Hexene, 1-heptene, 1-octene, 4-methyl-
Penten-1, 4-methyl-hexene-1, 4,4-dimethyl-pentene-1 and the like can be mentioned. MFR
Is smaller than the above range, the effect of improving the rigidity, transparency and heat resistance by the component (C) described later is poor, and when the MFR is larger than the above range, the thermoformability is poor. Also,
If the DSC characteristics deviate from the above range, the rigidity and heat resistance are inferior due to low crystallinity.

[0010] 2. Component (C) Nucleator A substance having a nucleator effect on a polypropylene resin (nucleator) is used for the purpose of improving the transparency of the component (A) and improving rigidity and heat resistance. (C) One or more kinds, and the amount is 0.03 to 2 with respect to the total amount of the composition.
It is blended in a ratio of weight%. If the amount is less than this, sufficient effects cannot be obtained.If the amount is more than this, it is excessive and not only is uneconomical, but also reduces transparency and causes smoke and odor during sheet molding. There is a risk of adverse effects such as Examples of the nucleating agent include the following substances. (C1) Aluminum di-para-tert-butyl-hydroxybenzoic acid represented by the following formula [1] (C2) 2,2 methylenebis (2,6-diphosphoric acid phosphate represented by the following formula [2] (C3) Cyclic organic phosphate ester polyvalent metal salt represented by the following formula [3] (C4) Sorbitol compound represented by the following formula [4] (C5) Rosins Metal salt

[0011]

Embedded image

In the above formula [3], R ¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ² and R ³
Is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, which may be different from each other.
Group II or Group IV metal atoms, X is a number of hydroxyl groups that is two less than the valency of the metal. In the formula [4], R ⁴ and R ⁵ are a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and may be different from each other. Note that the nucleating agents exemplified here are typical ones, and substances other than the examples may be used as long as they have the same effect as these. And the compounding method may be any method.

3. Component (B) Polyethylene-based resin Component (B) has 3 to 18 carbon atoms mainly composed of ethylene.
And α-olefins having predetermined characteristics. More specifically, a copolymer containing α-olefin having 3 to 18 carbon atoms as a comonomer together with ethylene as a main component, and the maximum peak temperature of this component (B) on an elution curve obtained by temperature-elution fractionation Is 15 to 85 ° C., preferably 25 to 82 ° C., and when the height of the peak is H and the width of the peak at one third of the height is W, the value of H / W is 2 .33 × 1
0 ⁻³ (° C. ⁻¹ ) or more, preferably 2.92 × 10
^-3 (° C. ⁻¹ ) or higher and MFR (JIS-K7210:
Temperature 190 ° C, load 2.16 kgf) 0.1 to 50 g
/ 10 min and a density of 0.93-0.88 g / cm ³
Is a polyethylene resin. When a polyethylene resin that does not fall under any of the above-mentioned properties is used, the resulting sheet is inferior in any of the performances of transparency, impact resistance, and thermoformability.

Here, the temperature rise elution fractionation (TREF: Te
mperature Rising Elution Fraction) means that once a polymer is completely dissolved at a high temperature, it is cooled, a thin polymer layer is formed on the surface of the inert carrier, and then the temperature is raised continuously or stepwise to elute the polymer eluted. In this method, the components are collected, and their concentrations and temperatures are continuously detected to determine the relationship between the amount of the polymer eluted and the elution temperature. A graph drawn by the elution amount (elution fraction) and the elution temperature is an elution curve, from which the composition distribution (molecular weight and crystallinity distribution) of the polymer can be known.

For details of the method and apparatus for measuring the temperature rise elution fractionation (TREF), see Journal of Applied Polym.
er Science Vol. 26 (1981) 4217-423
It is described on page 1. A commercially available measuring device includes a cross-separating device (CFC / T150A, manufactured by Mitsubishi Chemical Corporation). This cross sorter,
A temperature rising elution (TREF) mechanism that separates a sample by using the difference in melting temperature, and a size exclusion chromatograph (Size Exclusi) that further separates the separated fractions by molecular size.
on Chromatography (SEC) connected online.

In the present invention, the maximum peak on the elution curve refers to the peak having the highest peak height, that is, the peak having the highest elution fraction. Further, in the present invention, H /
W is the measured value of the maximum peak height (H) on the curve;
It can be calculated from the actually measured value of the peak width (W) at 1/3 of the height. Actually, as shown in FIG. 1, the width (W) of the peak is the height (1/3) on the elution curve.
It is obtained by drawing a horizontal straight line of H and measuring the distance between two points on the horizontal axis, which is closest to the maximum peak among the intersections of the curve and this straight line. Note that the actual measurement value (H or W) on the drawing can be a value in a correct unit (fraction or ° C) by performing appropriate correction as needed.

In the present invention, if the TREF characteristic of the component (B) polyethylene-based resin, that is, the maximum peak temperature and the H / W are within predetermined ranges, the composition distribution is narrow and the crystallinity is uniform, so that the component (A) When mixed with polypropylene resin, transparency is not deteriorated and rigidity and
Excellent impact resistance can be imparted while maintaining heat resistance at a practically sufficient level. On the other hand, if the maximum peak temperature is higher than the predetermined range, many high crystalline components are present, and the impact strength and transparency of a sheet in which the polyethylene resin is blended with the polypropylene resin are undesirably reduced. The same applies when the value of H / W is smaller than a predetermined range. On the other hand, if the maximum peak temperature is lower than the predetermined range,
This is not preferable because the rigidity and heat resistance of the sheet deteriorate.

The polyethylene resin having the above-mentioned various properties is a copolymer containing ethylene as a main component and an α-olefin having 3 to 18 carbon atoms as a comonomer component. As an α-olefin,
Specifically, propylene, 1-butene, 1-pentene, 1
-Hexene, 1-heptene, 1-octene, 4-methyl-pentene-1, 4-methyl-hexene-1,4,4-
Dimethyl-pentene-1 and the like can be mentioned. These comonomers are not limited to one type, and may be used as a multicomponent copolymer, for example, a terpolymer by using two or more types.

The proportion of the monomer units in the copolymer is preferably not less than 80 mol% of ethylene and not more than 20 mol% of the comonomer. Further, the method for producing the copolymer is not particularly limited, and the copolymer can be produced by a known method as long as the conditions satisfying the above-mentioned various properties are selected.
For example, a desired copolymer can be obtained by appropriately adopting a method of controlling the polymerization temperature or the comonomer amount as a known method for controlling the molecular weight and the distribution of crystallinity.

The polymerization catalyst and the polymerization method are not particularly limited. Examples of the catalyst include a Ziegler catalyst (that is, a catalyst based on a combination of a supported or unsupported halogen-containing titanium compound and an organoaluminum compound) and a Phillips catalyst. (Ie, those based on supported chromium oxide (Cr ⁶⁺ )), Kaminski-type catalysts (ie, those based on a combination of a supported or unsupported metallocene compound and an organoaluminum compound, especially an alumoxane), and the like. Since the component (B) in the present invention preferably has a relatively narrow composition distribution, it is particularly preferable to use a Kaminski type catalyst. Examples of the polymerization method include a slurry polymerization method, a gas-phase fluidized-bed polymerization method (for example, a method described in JP-A-59-23011) and a solution polymerization method in the presence of these catalysts, or a pressure of 200 kg / cm ^2. that's all,
A high-pressure bulk polymerization method at a polymerization temperature of 100 ° C. or higher is exemplified.

4. Blending of component (A) and component (B) In the present invention, the blending ratios of component (A) and component (B) are 50 to 85% by weight and 50 to 15% by weight, respectively, and component (B) is as defined above. When the amount is larger than the range, rigidity and heat resistance are inferior, and when it is smaller, impact resistance and thermoformability are inferior.

5. Other Components In the present invention, as the polyolefin-based resin composition which is a resin material forming a sheet, the above-mentioned component (A),
In addition to component (B) and component (C), auxiliary additives commonly used for polyolefins, such as antioxidants,
Neutralizing agents, heat stabilizers, light stabilizers, ultraviolet absorbers, antistatic agents, antifogging agents, slip agents, antiblocking agents, antibacterial agents, coloring agents and the like can be added. Further, as long as the properties of the present invention are not impaired, a rubber component composed of two or more α-olefins having 2 to 8 carbon atoms can be blended.

6. Formation of polyolefin-based resin composition Polyolefin-based resin composition, the above components, if necessary, dry blended, may be directly supplied to a sheet manufacturing apparatus and formed into a sheet, but before being supplied to a sheet manufacturing apparatus, A melt-kneaded material may be previously formed using an extruder, a Banbury mixer, a kneader-ruder, or the like, or the melt-kneaded material may be solidified and formed into granules of an appropriate size, and then supplied to a sheet manufacturing apparatus. That is, in the finally obtained sheet molded product, if the compounding amount of each component is within the above-mentioned range and the mixed state does not cause any practical problem, the compounding method of each component forming the polyolefin-based resin composition Alternatively, any steps may be used.

[7] Production of Sheet The production of the sheet in the present invention can be performed according to any known molding method, but in order to take advantage of the features of the present invention,
A method that can make both surfaces or one surface of the sheet smooth and glossy is preferable. Specifically, first, as a method for continuously producing a sheet, a resin material in a molten state is extruded into a flat plate shape, and this is continuously cooled and solidified while being sandwiched between a pair of rolls having a smooth surface. A method of using one or two belts having a smooth surface instead of a roll, a method of once solidifying a flat plate regardless of the surface smoothness, and heating the surface again to obtain a smooth surface. A method in which a flat roll or belt is pressed to finally obtain a sheet having a smooth surface, and a method in which a molten resin material is extruded into a cylindrical shape and cooled and solidified from the periphery by a water stream or an air stream. In addition, as a method of manufacturing discontinuously, a sheet that has been flattened by some method and has a non-smooth surface is placed between a pair of plates having a smooth surface, and the surfaces are pressed together while applying heat to smooth the surface. And a method in which a resin material in a molten state is supplied between a pair of plates having smooth surfaces and cooled and solidified while applying pressure by the plates. Among the manufacturing methods described above, from the viewpoint of quality stability and productivity, a method of continuously forming a roll or a steel belt with a smooth surface is preferable, and particularly a method of pressing with a steel belt from one side or both sides. Is preferred.

8. Laminated Sheet The sheet of the present invention may be a single-layer sheet or a multilayer sheet as long as it has a layer composed of the above-mentioned polyolefin-based resin composition. As a method for obtaining a multilayer laminated sheet having a layer made of the polyolefin-based resin composition, any method conventionally used for a polypropylene resin can be used. Specifically, in the above-described sheet forming process, a layer made of the polyolefin-based resin composition and a layer made of a desired material are laminated through a molten state through an adhesive resin as necessary, and then cooled and solidified. So-called co-extrusion method of forming a sheet, lamination method in which sheets that have been formed into a sheet are pasted together with a molten resin or an adhesive, etc .; A lamination method or an extrusion coating method may, for example, be mentioned. The sheet of the present invention is applicable to all fields in which performance can be improved by substituting the polypropylene resin layer for all laminates in which a polypropylene resin has been conventionally used.

9. Applications The sheet of the present invention has transparency, rigidity, heat resistance, impact resistance,
The thermoformability is excellent, and the thermoformed products obtained therefrom are also excellent in transparency, rigidity, heat resistance, and impact resistance.
Excellent heat resistance, impact resistance, and gloss. Therefore, it can be applied to the following applications.

(1) Stationery sheets and the like Polypropylene sheets are conventionally used for forming file covers, various cases, and the like by forming creases, bonding other parts, or bending and bonding them to form a tube or box. Have been. Such stationery sheets often require transparency, and the higher the rigidity, the better in terms of thinning and weight reduction of the product, and the more difficult it is to crack because it is used under various conditions. Therefore, the present invention is suitable for such uses.

(2) Packaging Containers, etc. Packaging containers are often required to have transparent contents.
Although the higher the transparency, the more preferable it is, the impact resistance of such a polypropylene sheet has been limited so far, for example, none of them can be used for freezing. On the other hand, the packaging container is required to have the function of withstanding the falling, overturning, and shock during transportation, and to maintain the hermeticity and protect the contents, so that the higher the impact resistance is, the more preferable it is. The only option was to sacrifice transparency. In the food field, heat resistance is required to withstand heat sterilization such as heating and cooking by microwave heating, boil processing, retort processing, etc.However, conventionally, sufficient transparency and impact resistance can not be obtained at the same time. could not. Naturally, the higher the rigidity, the better, and even at the expense of transparency and impact resistance,
This will impair the practicality of the packaging material. The present invention solves all of these problems simultaneously, a container,
It is suitable for use in packaging materials such as lids and trays. When used as a packaging container, after the sheet is heated to a molten or semi-molten state, it is pressed into a mold by air pressure or the like, and cooled and solidified to obtain a molded product of a desired shape, so-called thermoforming. Although the sheet is often processed, the sheet according to the present invention is easily formed because the sagging due to its own weight during heating is small, and the transparency is hardly deteriorated even after the thermoforming step. It has the feature that molded articles can be obtained at high speed and with high yield, and can be said to be extremely suitable for packaging container sheets.

[0029]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Evaluations in the following Examples and Comparative Examples were performed by the following methods.

I. Resin Physical Property Evaluation Method (1) MFR (Melt Flow Rate ) The MFR of the component (A) is determined based on the melt flow rate (temperature 230) of JIS-K6758 “Polypropylene Test Method”.
° C, load 2.16 kgf). The MFR of the component (B) is determined according to JIS-K7210 “Flow test method for thermoplastics” under test condition 4 (temperature 190
° C, load 2.16 kgf).

(2) Differential scanning calorimetry (DSC) JIS-K7121 using a DSC device manufactured by Seiko.
A 5 mg sample of the component (A) was taken in accordance with the “Method for Measuring Transition Temperature of Plastics”, kept at 200 ° C. for 10 minutes, and then crystallized at 40 ° C. at a cooling rate of 10 ° C./min. The crystallization onset temperature and the crystallization peak temperature were measured from the curves. Subsequently, a melting peak temperature was measured from a DSC curve when the material was melted at a heating rate of 10 ° C./min.

(3) By temperature rise elution fractionation (TREF)
The elution curve of the component (B) measured by TREF was measured as follows. a. Measuring device: A cross-separating device (Mitsubishi Chemical Corporation, product name CFC / T150A) is used as a measuring device.
The measurement was performed according to the measurement method in the attached operation manual. This cross-separation apparatus includes a temperature-rise elution fractionation (TREF) mechanism for fractionating a sample using a difference in dissolution temperature, and a size exclusion chromatograph (SEC) for further fractionating the divided sections by molecular size. These are the devices connected by.

B. Sample solution: First, a sample to be measured (ethylene / α-olefin copolymer) is dissolved at 140 ° C. using a solvent (o-dichlorobenzene) at a concentration of 4 mg / ml and measured. Injected into the sample loop in the instrument. The following measurements were performed automatically according to the set conditions.

C. Separation of sample solution held in the sample loop by temperature difference elution: TREF column that separates using the difference in dissolution temperature (attached to a 4 mm inside diameter, 150 mm length device filled with glass beads as an inert carrier) 0.4 ml was injected into a stainless steel column). The sample was cooled at a rate of 1 ° C./min from 140 ° C. to 0 ° C. and coated on the inert carrier. At this time, a polymer layer is formed on the surface of the inert carrier in the order of high crystalline components (easily crystallized) to low crystalline components (difficult to crystallize). After holding the TREF column at 0 ° C. for another 30 minutes, 2 ml of the component dissolved at 0 ° C.
The mixture was injected from the TREF column into a SEC column (AD80M · S, 3 columns, manufactured by Showa Denko KK) at a flow rate of 1 ml / min. While fractionation by molecular size was being performed by SEC, the temperature of the TREF column was raised to the next elution temperature (5 ° C.) and maintained at that temperature for about 30 minutes. The measurement of each elution section by SEC was performed at intervals of 39 minutes. The following temperature was used as the elution temperature, and the temperature was raised stepwise. Elution temperature (° C): 0, 5, 10, 15, 20, 25,
30, 35, 40, 45, 49, 52, 55, 58, 6
1,64,67,70,73,76,79,82,8
5,88,91,94,97,100,102,12
0,140 ° C.

D. Elution curve drawing: The absorbance in proportion to the concentration of the polymer was measured with an infrared spectrophotometer attached to the solution separated by the molecular size using the SEC column (wavelength: 3.42 μm, detected by stretching vibration of methylene).
Chromatograms of each elution temperature section were obtained. Using the built-in data processing software, the baseline of the chromatogram of each elution temperature section obtained by the above measurement was drawn and subjected to arithmetic processing. The area of each chromatogram was integrated and an integrated elution curve was calculated. Further, this integrated elution curve was differentiated with respect to temperature to calculate a differential elution curve. The plot of the calculation results was output to a printer. The plot of the output differential elution curve is
The horizontal axis represents 89.3 mm per 100 ° C. of elution temperature, and the vertical axis represents the amount of differential elution (change per 1 ° C. expressed as a fraction with the total integrated elution being 1.0) of 0.1. Performed on a 5 mm scale. e. Maximum peak temperature and H / W: Next, from this differential elution curve, the temperature of the highest peak on the curve (maximum peak temperature: H) and the peak height of this maximum peak are set to H. The value of H / W was calculated by measuring the peak width (W) at one-half the height.

II. Sheet physical property evaluation method (1) Transparency (haze: haze value) Using a sheet obtained by the method described below, JIS-K
Measured according to 7105 “Testing method for optical properties of plastics”. The criterion is as follows based on the measured value (unit:%) of the haze value. ：: less than 10 ：: less than 10 to 20 ：: less than 20 to 40 ×: 40 or more

(2) Rigidity (flexural modulus) Using a sheet obtained by the method described below, JIS-K
Measured according to 6758 "Polypropylene Test Method". The criterion is as follows based on the measured value (unit: MPa) of the flexural modulus. ◎: 1500 or more ○: less than 1500 to 1300 △: less than 1300 to 1100 ×: less than 1100

(3) Impact resistance (weight drop impact) Using a sheet obtained by the method described below, the impact resistance at -30 ° C was evaluated as follows.

A. Outline of the test method: Referring to FIG. 2, a test piece (1) is fixed to a ring-shaped holder (2) to prepare a circular exposed portion having a diameter of 70 mm, and a tip having a diameter of 38.1 mm from a constant height at the center. Hemispherical plumb bob (3)
Drop. The load of the weight is changed step by step, the energy at which the probability of failure is 50% is determined from the relationship between the load and the frequency of failure using a predetermined formula, and the value of the fracture energy is calculated as follows:
The falling ball impact strength determined by this test method shall be used. b. Temperature adjustment of test piece: Ethanol cooled to a predetermined temperature with dry ice is used as a refrigerant, and the test piece is immersed in this for 3 minutes, taken out, and dropped by a weight within 5 seconds.

C. Weight drop: Test 5 test pieces under one load. Test with an appropriate load that is likely to break, and if a load (W ') is obtained at which a part (1 or more and 4 or less) of 5 test pieces breaks, the load gradually increases by a constant load (S), and the total breakage Is repeated until the load (W ′ + nS) is reached. On the other hand, from the initial load (W ′), the load is gradually reduced by the same constant load (S), and the process is repeated until the load (W′−n ′S) at which all five sheets are not broken. The load interval (S) is about 2 times the total breaking load (W '+ nS).
The standard is 0%. The test load has five standard levels.

D. Calculation: The 50% breaking energy (E) is obtained from the following equation. E = [WS (t / 100-1 / 2)] × H × 0.09
8 E: 50% breaking energy (J) W: Minimum load (kg) at which all test specimens (5 specimens) break S: Load interval (kg) during repeated test T: 5 specimens at each test load H: height (cm) from the test piece to the tip of the pyramid The criterion is a measured value of 50% breaking energy (unit:
Based on J), it is as follows. ◎: 15 or more ：: less than 15 △: less than 10 to 5 ×: less than 5

(4) Hanging Retentivity Using a sheet obtained by the method described below, a pair of far-infrared heaters arranged vertically in parallel at intervals of 20 cm were connected to 45
The sheet was heated to 0 ° C., and a sheet fixed to a frame of 30 cm square was inserted in the middle of the sheet and heated. 25 seconds after the start of heating, the amount of sag at the center due to melting was measured. The smaller the amount of sag, the easier it is to perform thermoforming and the higher the yield because it is not affected by uneven heating or fluctuations in molding conditions, and the productivity can be increased because molding can be performed with a wide line. . The criterion is as follows based on the measured value (unit: mm) of the amount of sag. ：: less than 10 ：: less than 10 to 20 △: less than 20 to 30 ×: 30 or more

(5) Heat resistance (deflection temperature under load) JIS-K7
152, using an injection-molded test piece prepared according to “Plastic-Injection-molded test piece of thermoplastic”.
The measurement was performed at a load of 0.45 MPa according to IS-K7191 “Plastics—Measurement of deflection temperature under load”. The criterion is based on the measured value of the deflection temperature under load (unit: ° C)
It is as follows. ◎: 130 or more ○: less than 130 to 120 Δ: less than 120 to 110 ×: less than 110

III. Forming of Sheet The sheet used for the evaluation was formed by the following apparatus and forming conditions. (1) Apparatus: Plastic Giken Co., Ltd., Polishing three-roll sheet forming machine Basic configuration: Single screw extruder (40φL / D = 28.2 units used) / feed block / coat hanger die / metal polishing 3 This roll take-up / wind-up machine (2) Conditions: a. Raw material adjustment: The component (A) and the component (B) were mixed by dry blending, supplied to an extruder of a sheet forming machine, and formed into a sheet while melting and kneading both components. When adding the component (C), the component (A) was previously melt-kneaded and used. In all of the examples and comparative examples described later, standard amounts of antioxidants and neutralizers were added.

B. Extrusion temperature setting: The extruder is 19
The temperature was set to 0 ° C, and the tip was set to 230 ° C while gradually increasing the setting. Thereafter, the connection pipe, feed block and die on the way were all set at 230 ° C. c. Lip opening: The opening of the die lip was 0.8 mm. d. Air gap: The distance from the die lip tip to the roll was 150 mm. e. Take-off machine: The cooling and solidification of the molten resin was carried out by a metal-polishing (mirror surface) roll three-series in-line type take-up machine. The inside of the roll was cooled by circulation of oil at a constant temperature, and the oil temperature at this time was all 60 ° C. The roll diameter is 30 cm. The gap between the rolls was 0.5 mm. f. Drawing speed: All molding at 2 m / min, 0.50 mm
A thick sheet was obtained.

IV. Molding of container The sheet obtained by the method III was heated to near the molten state, placed on an inverted frustoconical mold having an opening diameter of 60 mm, a depth of 50 mm, and a bottom diameter of 55 mm. After covering the mold, the space above the mold is sealed, and then immediately sucking air inside the mold and supplying pressurized air into the upper box to solidify the molten sheet while closely contacting the inside wall of the mold by vacuum pressurization. A cup-shaped molded product was obtained. Heating was performed from above and below with a pair of far-infrared heaters at 100 mm intervals, the heater temperature was 300 ° C., and the pressurized air pressure was 2 kgf / cm ² .

V. Method of Evaluating Moldability and Physical Properties of Molded Product The moldability and the physical properties of the obtained molded product in the thermoforming of the above IV were determined as follows. (1) a molded article obtained by molding of a vacuum pressure forming method, although the corner portion lacks sharpness in the state of insufficient heating, will eventually good state when gradually longer the heating time, and from there As the heating time is increased, the rigidity of the cup is reduced due to collapse of the thickness distribution such as the thickness of the side surface becoming thinner. At this time, the range of the heating time during which a good molded product was obtained was measured, and it was determined that the wider the range, the better the thermoformability. The detailed criterion is as follows based on the measured value (unit: second) of the heating time range. ：: 10 or more ：: Less than 10 to 7 Δ: Less than 7 to 4 ×: Less than 4 (2) Appearance The obtained molded article was evaluated for its appearance by observing its transparency and gloss. The criteria are as follows. ：: Very good ○: Excellent △: Normal ×: Poor (3) Thickness distribution The thickness distribution of the obtained good molded product was observed and evaluated. The criteria are as follows. ◎: Very good ○: Excellent △: Normal ×: Poor

VI. EXAMPLES <Example 1> A propylene homopolymer (MFR: 2.5 g / 10 min, melting peak temperature: 166) as the component (A)
° C, crystallization onset temperature: 133 ° C, crystallization peak temperature: 1
C1 aluminum-di-para-tert-butyl-hydroxybenzoic acid (manufactured by Dainippon Ink Co., Ltd., trade name: Al-
Using a melt-kneaded product to which 0.1 part by weight of (PTBBA) was added, a copolymer with hexene containing ethylene as a main component as component (B) (manufactured by Nippon Polychem Co., Ltd., trade name: Kernel KE028, MFR: 2.2 g) / 10 min, density: 0.
895 g / cm ³ , peak temperature of TREF elution curve:
A dry blend was obtained using 30 parts by weight of 58 ° C., H / W: 4.55 × 10 ⁻³ ° C. ⁻¹ ).

For the dry blend, the sheet molding (III) and the container molding (I)
V), and sheet properties (II), thermoformability, etc. (V) were evaluated. The results are shown in Table 1. The sheet is
It shows extremely high impact resistance, is very excellent in transparency and droop retention, and has high rigidity and heat resistance. In the thermoforming, the moldability, the appearance of the molded product, and the thickness distribution are excellent.

<Example 2> In Example 1, the mixing ratio of the components (A) and (B) was changed from 70% by weight to 80% by weight and from 30% by weight to 20% by weight, respectively. Obtained a dry blend in exactly the same manner.
As shown in Table 1, the results of the molding and evaluation show that the sheet is particularly excellent in rigidity, transparency, impact resistance, sag retention and heat resistance. In the thermoforming, the moldability, the appearance of the molded product, and the thickness distribution are excellent.

<Example 3> In Example 1, the component (A) was replaced with a propylene homopolymer (MFR: 1.0 g / 1).
0 minutes, melting peak temperature: 165 ° C, crystallization onset temperature: 1
32 ° C., crystallization peak temperature: 129 ° C.), the proportions of the components (A) and (B) were changed to 85% by weight and 15% by weight, respectively. , 2 methylenebis (2,6-di-tert-butylphenyl) sodium (trade name N, manufactured by Asahi Denka Co., Ltd.)
Except having changed to A-11), a dry blend was obtained in exactly the same manner. The results of molding and evaluation are shown in Table 1,
The sheet is particularly excellent in rigidity and heat resistance, and also has high impact resistance, transparency and droop retention. Thermoforming has good moldability, appearance, and thickness distribution.

<Example 4> In Example 3, the component (A) was replaced with propylene homopolymer containing 40% by weight of the same propylene homopolymer and 3% by weight of ethylene as a comonomer.
Ethylene random copolymer (MFR 1.3 g / 10 min)
A dry blend was obtained in exactly the same manner, except that the mixing ratio of the component (B) was changed to 20% by weight and the mixing ratio of the component (B) was changed to 40% by weight. As shown in Table 1, the results of the molding and evaluation show that the sheet is particularly excellent in transparency, and has high rigidity, heat resistance, sag retention and impact resistance. The molded article has particularly excellent appearance, good wall thickness distribution and good moldability.

<Example-5> Each of the layers having the composition described in Example-3 was provided on both surfaces of the layer having the composition described in Example-1 by a co-extrusion method. The thickness ratio of 1:
3: 1 (0.1: 0.3: 0.1 [mm]). As shown in Table 1, the results of molding and evaluation show that the sheet is excellent in rigidity, transparency, impact resistance, and sag retention. In the thermoforming, the moldability, the appearance of the molded product, and the thickness distribution are excellent.

VII. Comparative Example <Comparative Example 1> In Example 1, only the melt-kneaded product of the component (A) was used, and the component (B) was not blended. As shown in Table 1, the results of molding and evaluation show that the sheet is excellent in transparency, rigidity and heat resistance, but inferior in impact resistance and sagging retention. Thermoforming is inferior in formability and wall thickness distribution.

<Comparative Example 2> A propylene-ethylene copolymer or a polyethylene having a structural unit derived from propylene as a main component and having an amorphous or low crystallinity by copolymerization with ethylene, and a polyethylene component contained in the crystalline polypropylene. A sheet made of so-called ICP dispersed in a sheet. The sheet is excellent in impact resistance and sag retention, but inferior in transparency. In thermoforming, the appearance of a molded product is particularly poor.

<Comparative Example-3> A propylene-ethylene random copolymer having an MFR of 1.5 containing 3% by weight of ethylene as a comonomer and adding 0.1% by weight of C2 as a component (C). Although excellent in transparency, it is inferior in impact resistance, heat resistance and sag retention. In thermoforming, the appearance at the time of pressure forming is excellent, but the others are at normal levels.

<Comparative Example-4> In Example 1, the component (B) was replaced with a linear low-density polyethylene (L-LDPE: manufactured by Nippon Polychem Co., Ltd., trade name Novatec LL UF4).
22, MFR: 0.8 g / 10 min, density: 0.926 g
/ Cm ³ , maximum peak temperature of TREF elution curve: 89
° C, H / W: 0.992 × 10 ^-3 ° C ^-1 ) except that the dry blend was obtained. In the sheet, the polyethylene resin deviates from the scope of the present invention,
Since the composition distribution is wide and the crystallinity is high, the transparency is poor. The thermoforming is inferior to Example-2 in which the container appearance differs only in the polyethylene component.

<Comparative Example-5> The dry blend was prepared in exactly the same manner as in Comparative Example-4, except that the blending ratios of the components (A) and (B) were changed to 90% by weight and 10% by weight, respectively. I got In the sheet, the transparency is improved to some extent, but the impact resistance is reduced. In thermoforming, moldability and wall thickness distribution in vacuum forming are inferior.

<Comparative Example-6> In Example 1, the component (B) was replaced with a high-density polyethylene (HDPE: manufactured by Nippon Polychem Co., Ltd., trade name Novatec HD HJ560, MF).
R: 7.0 g / 10 min, density: 0.964 g / cm ³ ,
Maximum peak temperature of TREF elution curve: 98 ° C, H / W:
A dry blend was obtained in exactly the same manner, except that the temperature was changed to 10.16 × 10 ⁻³ ° C. ⁻¹ ). The sheet is inferior in transparency because the polyethylene resin has high density and crystallinity outside the scope of the present invention. Even in thermoforming, the appearance of the container is poor.

<Comparative Example 7> In Example 2, the component (B) was replaced with an ethylene-butene copolymer rubber (trade name: A-4085, manufactured by Mitsui Chemicals, Inc., MFR: 4.0 g / 10).
Min, density: 0.870 g / cm ³ ) except that the dry blend was obtained. Although the sheet has excellent impact resistance, it is inferior in rigidity, heat resistance, transparency and sagging retention. In thermoforming, the appearance of the container is particularly poor.

[0061]

[Table 1]

[0062]

According to the present invention, in the polypropylene sheet and the thermoformed product obtained therefrom, it is possible to achieve a high level of rigidity, transparency, heat resistance, thermoformability, and impact resistance, which were conventionally difficult. Thus, for example, it is excellent in transparency and can be used for applications requiring extremely high cold shock resistance such as frozen food packaging, and at the same time, has sufficiently high heat resistance and rigidity, and has a high heat resistance when obtaining a container or the like from a sheet. It has good workability even in the molding step, and the thermoformed product obtained is excellent in physical properties and appearance. INDUSTRIAL APPLICABILITY The present invention greatly expands the uses and functions of conventional polypropylene-based sheets, and is suitable as stationery and packaging materials.

[Brief description of the drawings]

FIG. 1 shows an example of measurement using an elution curve.

FIG. 2 is a conceptual diagram of an impact resistance measuring device.

[Explanation of symbols]

 1 Test piece 2 Ring-shaped holder

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // (C08L 23/10 23:08) B29K 23:00 B29L 7:00 9:00 (72) Inventor Takeshi Okamoto 1 Tohocho, Yokkaichi City, Mie Prefecture F-term in Yokkaichi Technical Center, Japan Polychem Co., Ltd. AK63B AL05A AT00B BA01 BA02 BA03 BA06 BA16 CA30A CA30B JJ03 JK01 JK10 JL01 JN01 YY00A 4F208 AA04 AA11 AA11C AA11E AB08 AG03 MA01 MB01 MG04 4J002 BB022 BB042 BB111 BB121 BB141 ED086EG 016

Claims (3)

[Claims] 1. The following component (A): a polypropylene resin 50
85% by weight, the following component (B) polyethylene resin 1
A polyolefin-based resin composition comprising 3 to 5% by weight of 50% by weight and 0.03 to 2% by weight of a component (C) nucleating agent. (A) 2 to 2 carbon atoms other than propylene as a comonomer
A crystalline polypropylene which may contain 20 α-olefins and has the following various properties. a) MFR (JIS-K6758) is 0.1 to 50 g /
10 minutes. b) The main melting peak temperature of this component on the curve obtained by DSC (JIS-K7121) is 160 ° C. or more, the crystallization start temperature is 130 ° C. or more, and the crystallization peak temperature is 125 ° C. or more. (B) α- having 3 to 18 carbon atoms containing ethylene as a main component
A copolymer with an olefin, having the following properties. c) The density is 0.93-0.88 g / cm ³ . d) MFR (JIS-K7210) is 0.1 to 50 g /
10 minutes. e) The maximum peak temperature of this component on an elution curve obtained by temperature-rise elution fractionation is 15 to 85 ° C, the height of the peak is H (unit: fraction), and H / W when the width of the peak is W (unit: ° C.)
Is 2.33 × 10 ⁻³ (° C. ⁻¹ ) or more. 2. A single-layer or multi-layer sheet having a layer comprising the resin composition according to claim 1. 3. A molded article obtained from the sheet according to claim 2.