JPS64979B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyolefin composition that has improved moldability and provides a molded article with a good surface condition. The present invention also relates to a polyolefin composition containing a novel lubricant. It is known to add a lubricant to improve the moldability of polyolefins when they are melted. Particularly recently, in order to improve the mechanical strength of polyolefins, such as impact strength, drop strength, stress cracking resistance, linear strength, knot strength, etc., efforts have been made to increase the molecular weight and narrow the molecular weight distribution of polyolefins. It is coming. However, on the other hand, such higher molecular weight and narrower molecular weight distribution lead to an increase in melt viscosity, which makes it difficult to form films, monofilaments, etc.
In the case of blow molding and extrusion molding of pipes, etc., there are problems in that molding becomes impossible, or even if molding is possible, the torque during molding increases and the surface of the molded product becomes rough. Furthermore, in the case of injection molding, short shots and uneven gloss of the molded product may occur. For this reason, proposals have been made to improve moldability by adding various lubricants. However, even if commonly used alkaline earth metal salts of higher fatty acids, such as calcium stearate and calcium 12-hydroxystearate, are blended, molding cannot be achieved, especially in the case of polyolefins with high molecular weight and narrow molecular weight distribution as mentioned above. Processability and the skin condition of the molded product are not significantly improved, and there is a problem that bleed-out occurs when a large amount is added to increase the lubricant effect. Other compositions containing alkali metal salts of higher fatty acids have also been proposed, but they have not yet achieved sufficient moldability and surface condition of molded articles. In view of the current situation, the present inventors conducted intensive research on a lubricant that can provide good molding processability for polyolefins, especially polyolefins with high molecular weight and narrow molecular weight distribution, and can prevent surface roughness of molded products. The inventors have discovered that the above-mentioned problems can be solved by using perfluoroalkylcarboxylic acid or its metal salt, which is not known to have a lubricating effect, as a lubricant, and have thus arrived at the present invention. That is, in the present invention, perfluoroalkyl carboxylic acid and perfluoroalkyl carboxylic acid group A, per 100 parts by weight of polyolefin,
At least one metal salt selected from the group consisting of metal salts selected from Group B, Group B, and Group A,
This is a polyolefin composition characterized in that it contains 0.3 parts by weight. It is known that fluoroalkyl groups are used to improve water and oil repellency, improve mold release properties, and improve antistatic properties because of their low surface energy properties. For example, the fact that fluoroalkyl polyoxyethylene ethanol is effective in preventing static electricity on vinyl chloride resin was reported in JP-A-Sho.
No. 54-14457. In addition, it is also known from Japanese Patent Publication No. 53-23271 that perfluoroalkyl acid-containing phosphoric acid esters are effective as mold release agents, that is, solid solution lubricating agents for urethane resins and epoxy resins with strong adhesive properties.
No. Furthermore, Japanese Patent Publication No. 4503/1973 discloses water and oil repellency. However, perfluoroalkyl carboxylic acids, which are a type of compound containing fluoroalkyl groups with such properties, have compatibility with polymers and thermal stability that are not found in solid solution lubricity such as mold release agents. The present inventors have revealed for the first time that the fluidity during melting can be improved by maintaining the following properties. Perfluoroalkyl carboxylic acid has the general formula
Although represented by CnF _2o+1 COOH, the perfluoroalkylcarboxylic acid used in the present invention preferably has a total carbon number of 6 or more, particularly 6 to 13. If the total number of carbon atoms is less than 6, volatility during molding becomes a problem, which is not preferable. In addition, perfluoroalkyl carboxylic acid metal salts include Group A such as lithium, sodium, and potassium, Group A such as magnesium, calcium, and strontium, and B group such as zinc and cadmium.
It is selected from metal salts with group A and group A such as aluminum, and metal salts with group A and group A, particularly lithium salts and magnesium salts are preferred. The total carbon number of the perfluoroalkylcarboxylic acid metal salt is 2 or more, but in consideration of properties such as deliquescent property, 6 to 13 is particularly preferred. Such perfluoroalkylcarboxylic acids can be produced, for example, by the telomerization method, in which 4-fluoroethylene is radically polymerized with perfluoroalkyl iodide, or by the telomerization method, in which 4-fluoroethylene, etc., is radically polymerized in the presence of a base or fluoride ions. It can be obtained by an oligomerization method in which anionic polymerization is performed, an electrolytic fluorination method in which chlorinated alkyl carbonyl is electrolyzed in hydrofluoric anhydride and then hydrolyzed, and the like.
Further, perfluoroalkylcarboxylic acid metal salts can be easily obtained by a neutralization reaction between perfluoroalkylcarboxylic acids and metal bases. Perfluoroalkyl carboxylic acid and perfluoroalkyl carboxylic acid metal salts may be used alone or in combination of two or more, and the preferred amount is 0.01 to 3.0 parts by weight, particularly 0.05 to 2.0 parts by weight, based on 100 parts by weight of polyolefin. A range of 50% is preferred.
If the blending amount is less than 0.01 part by weight, the effect of improving molding processability or improving the surface condition of the molded product will be small;
If it exceeds 3.0 parts by weight, on the contrary, the slip property at the screw part of the extruder increases, the molding processability decreases, and bleed-out is also likely to occur. Polyolefins containing perfluoroalkylcarboxylic acid and/or perfluoroalkylcarboxylic acid metal salts include polyethylene, polypropylene, polybutene-1, poly-4-methyl-1-pentene, poly-3-methyl-1-pentene, and polyolefin. It may be a copolymer of -3-methyl-1-butene and these with α-olefin or other monomers, or a mixture thereof. Various known methods can be used to blend the polyolefin and perfluoroalkylcarboxylic acid and/or perfluoroalkylcarboxylic acid metal salt. For example, after mixing each component using a ribbon blender, tumbler blender, Henschel mixer, etc., the components are melt-mixed using an extruder, Banbury mixer, two rolls, etc., or dissolved in a melt of hydrocarbons or aromatics and mixed into a polymer solution. One method is to do so. The polyolefin composition thus obtained not only improves the molding processability in extrusion molding and injection molding, but also improves the surface condition, slip properties, antifogging properties, antistatic properties, etc. of molded products. The polyolefin composition of the present invention may also contain weather-resistant stabilizers, heat-resistant stabilizers, antistatic agents, antifogging agents,
Various additives such as anti-blocking agents, slip agents, pigments, dyes, etc. which are usually added to polyolefins may be added to the extent that the purpose of the present invention is not impaired. Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples in any way unless the gist of the invention is exceeded. Example 1 Density 0.954g/cm ³ , Melt index 0.9g/
10min polyethylene (HIZEX 5000S;
Mitsui Petrochemical Industries) 100 parts by weight, dilauryl thiodipropionate and 3,5-
0.3 parts by weight and 0.1 parts by weight of di-t-butyl-4-hydroxytoluene, respectively, and 1 part by weight of lithium perfluorocaprylate were mixed in an extruder with a screw diameter of 20 mmφ and L/D = 26. Granulation was carried out at ℃. The screw diameter of the granulated polyethylene
20mmφ, L/D=20 extruder with nozzle diameter 1mmφ,
A nozzle with L/D = 15 was installed, and a full-flight type screw was used to perform spinning at a resin temperature of 260°C while changing the screw rotation speed.The extrusion pressure relative to the extrusion amount was measured, and at the same time the surface of the undrawn yarn molded product was measured. The smoothness was observed. The results are shown in Table 1 and Figure 1. Comparative Examples 1-2 Calcium 12-hydroxystearate was used instead of lithium perfluorocaprylate in Example 1, or it was not mixed at all. The results are shown in Table 1 and Figure 1.

[Table] (3) Molded products with smooth and glossy surfaces ○, rough and lackluster surfaces ×
Examples 2 to 8 In place of lithium perfluorocaprylate in Example 1, the compounds shown in Table 2 were used. The results are shown in Table 2.

【table】

[Table] Examples 9 to 11 The amount of lithium perfluorocaprylate in Example 1 was changed as shown in Table 3. The results are shown in Table 3.

[Table] Note (4) Parts by weight Examples 12 to 13 Lithium perfluorocaproate and lithium perfluorolaurate were used in place of lithium perfluorocaprylate in Example 1. 4th result
Shown in the table.

[Table] Examples 14 to 16 and Comparative Examples 3 to 4 Density 0.91 g/cm ³ , Melt index 1.5 g/cm 3
100 parts by weight of polypropylene (Mitsui Petrochemical Polypropylene J-300; Mitsui Petrochemical Industries) was added with Irganox 1010 and 3,5-di-propylene as stabilizers.
t-butyl-4-hydroxytoluene, respectively
0.1 part by weight, 0.1 part by weight were blended, and further 1 part by weight of the compound shown in Table 5 was blended and granulated at 250°C. The granulated polypropylene was spun in the same manner as in Example 1. The results are shown in Table 5.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the present invention and a comparative example.

Claims (1)

[Claims] 1. Perfluoroalkylcarboxylic acid and at least one metal salt of perfluoroalkylcarboxylic acid selected from Group A, Group A, Group B, and Group A per 100 parts by weight of polyolefin. ,
A polyolefin composition comprising 0.01 to 3.0 parts by weight. 2 The number of carbon atoms in perfluoroalkylcarboxylic acid is 6
13. The polyolefin composition according to claim 1. 3. The polyolefin composition according to claim 1, wherein the perfluoroalkyl carboxylic acid metal salt has 2 to 13 carbon atoms.