JPS63102933A - Propylene group polymer laminated sheet - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

μ 1 The present invention relates to a propylene-based polymer laminate sheet formed by laminating a propylene-based polymer (A) on one or both sides of another propylene-based polymer (B), and which has good gloss. The object of the present invention is to provide a propylene-based polymer laminate sheet that has excellent transparency and is easy to vacuum form.

[Suitechi] Opropylene polymers are industrially produced due to their good processing methods, excellent flexibility, high softening point, and high rigidity and hardness, and can be molded into various shapes. and is used in many fields. As one of them, those molded into films and sheets are subjected to secondary molding by vacuum forming, pressure forming, hot plate heating type air pressure thermoforming, etc., and are widely used for various containers. However, propylene-based polymers have the drawback of insufficient transparency due to their high crystallinity, and their uses are often limited. For this purpose, methods for improving the transparency of propylene polymers include, for example, a method of blending an organic carboxylic acid into the polymer (Japanese Patent Publication No. 39-180!3);
A method of blending an organic carboxylic acid 7, ε minirum salt (Japanese Patent Publication No. 1852/1982), a method of blending dibenzylidene sorbitol (Japanese Patent Application Laid-open No. 22740/1989), etc. have been proposed. However, these methods do not have satisfactory transparency effects, especially when the sheet is subjected to secondary forming processing such as vacuum forming, pressure forming, hot plate heating type air pressure forming, etc. The sheets tend to sag during heating, resulting in wrinkles in the molded product and uneven wall thickness.Also, in hot plate heating type air pressure forming, the hot plate heating temperature is high and the molding cycle is long. have. Also, a method has been developed for improving the transparency of a propylene polymer by directly introducing the molten propylene polymer extruded through a T-die or circular die into a water bath. However, according to this method, it is possible to obtain a transparent propylene polymer sheet. However, when this sheet is subjected to secondary forming processing such as vacuum forming, pressure forming, hot plate heating type air pressure forming, etc., there is a drawback that the transparency is extremely deteriorated by the heat applied during forming. In addition, it has been developed to improve the transparency of a propylene polymer sheet by preparing a propylene polymer original sheet extruded by a T-die and subjecting it to -axial stretching, two-wheel stretching, or rolling. However, when a transparent sheet obtained by these methods is subjected to secondary molding processing in the same manner as described above, not only the transparency deteriorates extremely, but also the molding processability such as shrinkage of the sheet during preheating deteriorates extremely. There is a drawback that it does. I'll do it. From the above, the present invention does not have these problems (defects), and has excellent secondary molding processability such as vacuum forming, pressure forming, hot plate heating pressure air aging type, etc. The object of the present invention is to obtain a propylene polymer sheet that has excellent transparency even when subjected to secondary molding. According to the present invention, these problems are caused by a sheet formed by laminating a propylene polymer (A) with another propylene polymer (B) on one or both sides of the propylene polymer (A). Melt flow index (JIS) of polymer (A)
Measured according to K7210 under conditions 14, below r
MFRJ) is 0.01 to 4.5 g/10 min, and the NFR of the propylene polymer (B) is 5.0.
~50 g/10 min, propylene polymer (
A) a propylene-based polymer relative to the layer thickness; and (B) a propylene-based polymer laminate sheet having a layer thickness of 0.01 to 0.8. The present invention will be explained in detail below. (A) Propylene polymer The propylene polymer (A) and propylene polymer (B) used in the present invention are both
- Crystalline propylene homopolymers with a heptane extraction residue of at least 70%, as well as random and block copolymers of propylene with ethylene or other α-olefins (usually having at most 12 carbon atoms). The copolymerization proportion of the random and block copolymers with ethylene and α-olefin is usually at most 20% by weight (preferably not more than 15% by weight) based on their total amount. MFR of propylene polymer (A) is 0.01 to 4.5
g/10 minutes, preferably 0.05 to 4.5 g/10 minutes, and particularly preferably 0.1 to 4.0 g/10 minutes. Further, the MFR of the propylene polymer (B) is 5.
0 to 50 g/10 minutes, 5.0 to 45 g 71
0 minutes is preferable, and 5.0 to 40 g/10 minutes is particularly preferable. MFR of propylene polymer (A) is 0.01g
If the time is less than 710 minutes, the moldability is not good; on the other hand, 4.
If it exceeds 5 g/10 minutes, the resulting sheet will not have good formability when subjected to secondary forming processes such as vacuum forming and pressure forming, and the MFR of the propylene polymer (B) will be poor.
If the amount is less than 5.0 g/10 minutes, the resulting sheet will have poor transparency and gloss. On the other hand, if it exceeds 50 g/10 minutes, the moldability will be poor when producing a multilayer sheet. The propylene polymer (A) and the propylene polymer (B) of the present invention may each be used as is. 2 Furthermore, the propylene polymer (A) and propylene polymer (B) of the present invention may be used as a low-density ethylene polymer having a density of 0.900 to 0.935 g/c. may be further blended, and a metal salt of carboxylic acid may be blended (added) as a nucleating agent.In the present invention, even when these low density ethylene polymers are blended. Even when a metal salt of carboxylic acid is blended, both propylene polymer (A) and propylene polymer (B)
It is necessary that the MFR of each of the above-mentioned MFRs is within the above range. (Japanese) Low-density ethylene polymer The density of this ethylene polymer is 0.900 to 0.935.
g/CmJ, 0.3O5~0.930 g/
cm" is preferable, especially 0.905 to 0.9
25 g/cm". This low-density ethylene polymer may be a so-called high-pressure polyethylene polymerized using a free radical initiator, or a linear polymer having a short alkyl side chain. Ethylene-based polymers may also be used. The high-pressure polyethylene has a very large number of carbon atoms in the side chain compared to the main chain, and generally has a long side chain with 10 or about the same number of carbon atoms as the main chain. However, in linear ethylene polymers, the number of carbon atoms in the side chain is mainly 1 to 10.The number of side chains is 10 to 10 carbon atoms in the main chain.
Generally, it is 2 to 35 pieces per 00 pieces. In the presence of a so-called Ziegler or Phillips catalyst, this linear ethylene-based polymer is produced by combining ethylene with a carbon number of at most 1.
It is obtained by copolymerizing two α-olefins. Representative examples of these α-olefins include propylene, butene-1, hexene-1, octene-1, and octene-1.
-Methylpentene-1. The melt flow index (measured according to JIS K7210 under conditions 4, hereinafter referred to as rM, 1.) of these low density ethylene polymers is usually 0.1 to Bo
g/10 minutes, particularly preferably 0.1 to 60 g/10 minutes, and the low density ethylene polymer is blended with 100 parts by weight of the propylene polymer (A) or propylene polymer (B). The proportion is generally at most 30 parts by weight, preferably from 1 to 30 parts by weight. (4) Metal salts of carboxylic acids The metal salts of carboxylic acids used as nucleating agents in the present invention refer to metal salts of aliphatic carboxylic acids, aliphatic dicarboxylic acids, aromatic carboxylic acids, or aromatic dicarboxylic acids. metal salts of their alkyl-substituted derivatives, in particular, for example, the sodium, potassium, calcium or aluminum salts of stearic, adipic or sepatic acids, the sodium salts of benzoic acid or Valer's tert-butyl - Preferred examples include aluminum salts of benzoic acid. The blending amount is 0.01 to 0 per 100 parts by weight of the propylene polymer (A) or propylene polymer (B).
．． 5 parts by weight, and if it is less than the lower limit, there is no effect of improving transparency. Dibenzylidene sorbitol can be used as a commercially available product, and the blending amount is preferably 0.03 to 1 part by weight, and if it is less than the lower limit, the transparency will be If metal salts of carboxylic acids and dibenzylidene sorbitol, which have no improvement effect, are added in excess of their respective upper limits, not only will there be problems economically, but they will also bleed onto the surface of the sheet and the final molded product. Sometimes. In addition, when adding a metal salt of carboxylic acid and dibenzylidene sorbitol in combination, the metal salt of carboxylic acid is 0.03
~1 part by weight, preferably 0.05-0.5 part by weight, dibenzylidene sorbitol 0. O] ~0.5 parts by weight, preferably 0.03 to 0.2 parts by weight, and if the amount of dibenzylidene sorbitol and metal salt is outside the above range, dibenzylidene sorbitol and metal salt of carboxylic acid The relative balance between the two is disrupted and transparency is not achieved. (D) Mixing method In producing the sheet of the present invention, a stabilizer against oxygen, ultraviolet rays, and heat, which is commonly used in the field of olefin polymers, is added to the propylene polymer (A) and the propylene polymer (B). Additives such as flame retardants, lubricants, bactericidal agents, antistatic agents, and colorants (pigments) may be added to the extent that they do not significantly reduce the transparency of the sheet. Even when the ethylene polymer or metal salt of carboxylic acid is blended with each propylene polymer, or when the additives are blended, it is necessary to uniformly mix each blended component. As a mixing method, a mixer such as a Henschel mixer, which is commonly used in the field of synthetic resins, may be used to tri-blend, or a mixer such as a Nigu, extruder, or Banbury mixer may be used to blend the molten state. You may also mix it with At this time, a more homogeneous mixture can be obtained by tri-blending in advance and further melt-kneading the resulting mixture. In this case, the resulting mixture is preferably formed into pellets for sheet formation as described later. (E) Laminated sheet and method for manufacturing the same In order to manufacture the laminated sheet of the present invention, a sheet of propylene polymer (A) and a sheet of propylene polymer (B) (
Each propylene polymer may be used alone, or may be blended with the low density ethylene polymer and carboxylic acid metal salt)
The sheets may be laminated by a commonly used method, or the sheets may be continuously produced while producing the propylene polymer (A) and the propylene polymer (B) respectively. You may. In this case, if the propylene polymer (A) layer is "three layers" and the propylene polymer (B) layer is "r II layer", the layer structure may be one layer/■ layer, It may be three or more layers like the engineering layer. Among the 11 layers thus produced, the thickness of the propylene polymer CB) layer relative to the thickness of the propylene polymer (A) layer is 0.01 to 0.8, and 0.05 to 0. 8 is desirable, and 0.1 to 0.6 is especially suitable. If the thickness of the propylene polymer (B) layer is less than 0.01 with respect to the thickness of the propylene polymer (A) layer, it is difficult to produce a laminated sheet having a uniform thickness. On the other hand, if it exceeds 0.8, the moldability is poor. The thickness of the laminated sheet thus obtained is usually 0.1
~2.0 ms, preferably 0.2 to 2.0 ff1m, particularly preferably 0 to 1.51. If the thickness of the a-layer sheet is less than 0.1 mm, it is difficult to manufacture. On the other hand, if the thickness of the laminated sheet exceeds 2.0cm,
The moldability is not good during the secondary molding process described below. Various molded products can be obtained by subjecting the propylene polymer sheet thus obtained to secondary molding processes such as vacuum forming, pressure forming, and hot plate heating type air pressure thermoforming. This secondary molded product also has excellent transparency. - The present invention will be explained in more detail below with reference to Examples. In addition, in the Examples and Comparative Examples, the haze is determined by ASTM
Measured in accordance with 01003-1111. In the examples and comparative examples, the mixture components used were M
Propylene homopolymer with FR of 0.5 g/10 min [hereinafter referred to as rPP(1) J], MFR of 740 g
Propylene homopolymer [hereinafter referred to as “PP(2
)", a random copolymer of propylene and ethylene with an MFR of 0.13 g/10 min (ethylene copolymerization ratio 5.0% by weight, hereinafter referred to as rPP(3) Propylene homopolymer [hereinafter referred to as rPP(4) J], MF
Random copolymer of propylene and ethylene with R of 5.5 g/10 min [copolymerization ratio of ethylene: 4.8% by weight, hereinafter referred to as rPP(5)J], MFR of 8.0 g
Random copolymer of propylene and ethylene with 710 min [copolymerization ratio of ethylene 5.2% by weight, hereinafter rP
P(8) J], a propylene homopolymer with an MFR of 80 g/10 min [hereinafter referred to as rPP(7) J,
), M, 1. 2. Low-density ethiolene-based polymer with short chain branching of Og / 10 min [number of short chains (methyl groups) per 1000 carbon molecules in the main chain: 18, density 0.920 g / cm", hereinafter referred to as rPEJ ] and sodium salt of benzoic acid (hereinafter referred to as rBz-NaJ) as a metal salt of carboxylic acid. Examples 1 to 8, Comparative Examples 1 to 6 (However, Examples 2, 5.6 and 7 were
10 parts by weight of PE was added to 100 parts by weight of each propylene polymer in the layer, and in Example 3, 0.1 part by weight of Bz-N was added to 100 parts by weight of the propylene polymer in one layer.
In Examples 4.5 and 7, 0.1 part by weight of Bz-Na was added to 100 parts by weight of each propylene polymer in the three layers and the layer (1).
Using a multi-manifold type T-type two-type three-layer die sheet forming machine with a two-layer extruder of +am and 40 mm, the temperature at the exit of the die was 230°C and the total thickness was 0.4 mm. A sheet of two types and three layers (three layers/II layer/work layer) with a width of 250 mm and a width of Table 1 shows the degree of haze of the sheets obtained.The ratio of the thickness of the
So, 1). Each sheet produced in this way was vacuum formed using a continuous roll forming test machine (manufactured by Asano Research Institute, model FLX-02, sheet width 245+am, oven type, double-sided infrared heating system, with plug), and is +00mm+
A container with a width of 100 mm and a depth of 50 am was created. The degree of haze at the bottom (thickness: 0.3 mm) of this container was measured. Furthermore, the state of the apparent molded product was observed. The results are shown in Table 1. In addition, in Comparative Examples 1.3.4 and 5, secondary forming processing such as vacuum forming could not be performed. Furthermore, in Comparative Example 6, the sheet could not be stably manufactured. Example 9 PP (2) was extruded as the II layer using a T-die film forming machine (
Diameter Hmm, die width 1000! +111), the resin temperature is 230℃, the thickness is 40gm, and the width is 700H.
obtained the film. In addition, PP (1) was used as one layer in a single layer sheet forming machine (diameter
A single-layer sheet is extruded using a PP (135 mm), and the above-mentioned PP (2) film is pasted on the cooling roll portion (usually called the roll pressure bonding method). The thickness ratio was 0.11). The degree of haze of the obtained laminated sheet was measured, and the state of the apparent molded product was also observed and the degree of haze was measured. The results are shown in Table 1. Before laminating the II layer film of the laminated sheet thus obtained, gravure printing was performed, and the printed sheet was laminated in the same manner as described above. The obtained laminated sheet was beautiful. Comparative Example 7 A raw sheet with a thickness of 1.2 mm was prepared by extruding PP (3) using an extruder at a resin temperature of 230° C. through a T-die with a width of 400 mm. This raw sheet was rolled at a temperature of 130° C. using a pair of pressure rolls with a diameter of 300 mm and a surface length of 600 mm. The final sheet thickness was 0.4 mm. Although this sheet was transparent, it could not be subjected to secondary forming processes such as vacuum forming. Comparative Example 8 A raw sheet was extruded from a T-die in the same manner as Comparative Example 7. Next, a sheet having a thickness of 0.38 mm was manufactured by placing the sheet in a water bath with a water temperature of 20° C. with a gap of 60 mm. The resulting sheet was transparent. This sheet was vacuum formed in the same manner as in Example 1. As shown in Table 1, the resulting container had poor transparency. (Margin below) Table 1 (Part 1) 1) ■: Beautiful, good 0: Generally beautiful, good Table 1 (Part 2) 1) o: Beautiful, good O: Generally beautiful, good 2) Thickness ratio The propylene polymer laminated sheet of the invention can not only be easily manufactured in the same way as ordinary propylene polymer laminated sheets, but also has sufficient heat resistance to be suitable for retort processing. The surface of the sheet is also beautiful. Moreover, even when subjected to secondary forming processing such as vacuum forming, the transparency is not impaired. Because the laminated sheet has such characteristics, it can be used as a container, its lid, a cassette case for a VTR, etc. by secondary molding. In particular, since it can be retorted and heated in a microwave oven, it can be used in a wide range of applications, such as containers and lids for which these treatments are performed.

Claims (1)

[Claims] A sheet formed by laminating a propylene polymer (A) with another propylene polymer (B) on one or both sides,
The melt flow index of the propylene polymer (A) is 0.01 to 4.5 g/10 min, and the melt flow index of the propylene polymer (B) is 5.0 to 4.5 g/10 min.
50 g/10 minutes, and the thickness of the propylene polymer (B) layer relative to the thickness of the propylene polymer (A) layer is 0.
A propylene-based polymer laminate sheet having a molecular weight of 01 to 0.8.