JPS6123634A - Polypropylene composition for extrusion coating - Google Patents

Abstract

PURPOSE:The titled composition which can be extruded at a high speed and is highly improved in surface roughness, comprising a heat-treated PP and a specified PE. CONSTITUTION:A heat-treated PP (A) of a melt flow rate (MFR) of 0.3-100g/ 10min is obtained by mixing 100pts.wt. (a) PP resin of a MFR of 0.1-20g/10min with 0.002-0.2pt.wt. (b) peroxide having a one-min half-life temperature near the melting temperature of component (a) (e.g., t-butyl peroxyacetate) and heat-treating the mixture by melt kneading at 180-280 deg.C for 1-10min. 60-95wt% component A is mixed with 40-5wt% (B) PE having a crystallinity as determined by X ray analysis >=25%, or alternately, 100pts.wt. resin composition formed by mixing 60-95wt% component (a) with 40-5wt% component B is further mixed with 0.002-0.2pt.wt. component (b) and the resulting mixture is heat-treated by melt kneading at 180-280 deg.C for 1-10min.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polypropylene composition for extrusion coating, which can be molded at high speed and has significantly improved surface roughness of coated molded articles.

Polypropylene resin has excellent mechanical properties, heat resistance, and chemical resistance, so its use in extrusion coatings has been expanding in the market in recent years.

However, since polypropylene resin has extremely low melt elasticity during melt processing, it is known that significant surface roughness occurs on the coated surface during high-speed processing and molding, which is a requirement of the current generation. .

For this reason, when polypropylene resin is used as an extrusion coating material, high-speed molding is impossible.

Therefore, in order to improve the extrusion coating moldability of polypropylene resin, a polypropylene composition in which polyethylene was blended with polypropylene resin was proposed, but this composition also caused surface roughness on the coated molded product, so it was molded at high speed. cannot be used for

The inventors completed the present invention as a result of intensive research aimed at solving the above-mentioned problems of polypropylene resin as an extrusion coating material.

That is, the present invention uses 60 to 95 parts by weight of heat-treated polypropylene obtained by heat-treating a polypropylene resin in the presence of peroxide, and a polypropylene having a crystallinity of 25% by X-ray analysis.
The present invention relates to a polypropylene composition for extrusion coating with improved moldability, which is obtained by mixing 5 to 40 parts by weight of polyethylene in a total amount of 100 parts by weight.

Furthermore, the present invention provides a resin mixture in which 60 to 95 parts by weight of a polypropylene resin and 5 to 40 parts by weight of polyethylene having a degree of crystallinity of 25 or more by X-ray analysis are mixed so that the total of these parts is 100 parts by weight. The present invention relates to a polypropylene composition for extrusion coating which has improved moldability and is obtained by heat treatment in the presence of peroxide.

A polypropylene composition obtained according to the present invention.

The polypropylene resin used in the present invention includes crystalline polypropylene homopolymer, crystalline ethylene propylene random copolymer, etc. Polypropylene, such as crystalline ethylene propylene block copolymer, is commonly used in the market.

Ren resin. The melt flow rate of the polypropylene resin is preferably 0.1 to 2 of 710 minutes.

The polypropylene resin may be blended with conventionally known additives such as an antioxidant, a copper damage inhibitor, a slip agent, and a surfactant.

A further one is used in the present invention. The S-oxide is preferably an organic peroxide having a 1-minute half-life temperature near the melting temperature of polypropylene resin.

These include, for example, t-butyl-peroxyacetate, t-butyl-oxybenzoate, dicumyl peroxide, t-butylperoxyisopropyl carbonate, di-t-butylperoxyphthalate+2.5 -dimethyl-2,5-di(penzoylno(-oxy)hexene-ro, 2,5-dimethyl-2,5-di(t-butylno-2-oxy)hexane, t
-butylno-2-oxylaurate, t-butylperoxymaleic acid, methyl ethyl ketone peroxide, and t-F-F-/L/cumyl peroxide.

In particular, as the peroxide, a powdered peroxide consisting of a mixture of the above-mentioned organic peroxide and highly dispersed silicic acid anhydride can be suitably used.

The peroxide is preferably blended in an amount of 0.002 to 062 parts by weight per 10 parts by weight of the polypropylene resin.

The heat treatment of the polypropylene resin involves adding peroxide to the polypropylene resin, preferably in a state where the polypropylene resin is molten, particularly in an extruder to a temperature of 180 to 28
This is carried out by melt-kneading and heat-treating at a temperature of 0° C. for about 1 to 10 minutes.

The heat treatment is performed until the melt flow rate of the heat-treated polypropylene is 0. '5~1001il/10min, especially 1~30
It is preferable to carry out the process so that 'fi' is 710 minutes.

The polypropylene composition for extrusion coating of the present invention.

Heat-treated polypropylene 60 obtained as described above
95 parts by weight, preferably 70 to 90 parts by weight, and 5 to 40 parts by weight, preferably 10 to 30 parts by weight of polyethylene having a degree of crystallinity of 25% or more by X-ray analysis, the total of these being 1
00 parts by weight.

The crystallinity according to the X-ray analysis used in the present invention is 2.
Examples of polyethylene containing 5% or more include medium density polyethylene, high density polyethylene, linear low density polyethylene, and the like.

If the blending ratio of polyethylene is less than the lower limit, the effect of improving the extrusion coating moldability of the polypropylene resin will be small; It is not preferable because the properties of

Alternatively, the polypropylene composition for extrusion coating of the present invention contains 60 to 95 parts by weight of polypropylene resin.

Preferably 70 to 90 parts by weight and 5 to 4 parts by weight of the polyethylene.
0 parts by weight, preferably 10 to 30 parts by weight, into a resin mixture such that the total of these parts is 100 parts by weight,
Preferably 0.00 parts by weight per 100 parts by weight of polypropylene resin.
0.002 to 0.2 parts by weight of said peroxide are added and the mixture is heated, preferably in the state where the resin mixture is molten, at a temperature of 1 to 1
It can be obtained by melt-kneading and heat-treating for about 0 minutes.

If the mixing ratio of the polypropylene resin and polyethylene is outside the above range, the two objects of the present invention cannot be achieved.

The heat treatment is performed when the melt flow rate of the polypropylene composition for extrusion coating is 0.5 to 1002/10 minutes, particularly 1 to 1002/10 minutes.
It is preferable to do this in such a way that the total amount of water is 71 o.

The polypropylene composition for extrusion coating of the present invention includes:

Conventionally known additives such as antioxidants, ultraviolet absorbers, copper inhibitors, slip agents, surfactants, flame retardants, pigments, conductive substances, and ethylene propylene copolymer rubber (EP
R, zpDn), inorganic/organic fillers, and other third components may be blended within a range that does not impair the purpose of the present invention. These additives may be added when manufacturing the final product, or may be added to each component in advance.

The polypropylene composition for extrusion coating of the present invention.

It can be used as a coating material for electric wires and metal plates.

Examples and comparative examples are shown below. On each side below, the melt flow rate was measured according to AEITM D1238, where H means heavy air accumulation.

Example 1 To 100 parts by weight of powder of a crystalline ethylene propylene block copolymer having a melt flow rate of 0.3 y/1o and an ethylene content of 6.0%, 15 parts by weight of BHTo and 0.3 parts by weight of Arganox 1010 were added.

Carunium stearate 0.1 part by weight, copper damage inhibitor 0.
0.08 parts by weight of a powdered peroxide consisting of a mixture with highly disperse silicic anhydride containing 6 parts by weight and 40% by weight of 2,5-dimethyl-2,5-di(1-butylperoxy)hexane After tri-blending, the maximum temperature 2
The mixture was melt-kneaded in an extruder at 60°C and heat-treated to form pellets. The melt flow rate of the pellet was 6.1 f710 min.

A polypropylene composition for extrusion coating was obtained by triblending 20 parts by weight of high-density polyethylene (grade name 1s5003B, manufactured by Showa Denko ■) with 80 parts by weight of Cono pellets.

Using this composition as a high-speed molding material, a high-speed wire coating test was conducted using the following method.

Equipment: Japan Steel Works ■65-1200 improved high speed wire coating molding machine Molding conditions: Core wire diameter: 0. East covering diameter: 0.66'yn Linear velocity: 600 m/min + 800? 7Z/min Molding temperature: C! , 200°C IC2230°C.

03250℃, 04250℃.

05250°C The surface roughness of the obtained covered wire is defined as the center line average roughness (Ra)
It was measured as

In particular, the center line average roughness (Ra) is defined as the roughness of a rough curve (obtained by excluding the long wavelength part), where a part of measurement length t is sampled, and the center line of the sampled part is taken as the X axis. When we express the curve as y=f (x).

Ra-2-fZ l f(x) 1dxt.

The RaO value given by is expressed in μm.

The surface roughness of the coated wire was judged based on the center line average roughness (Ra) and the feel of the wire.

The results are summarized in Table 1.

, Example 2 615 parts by weight of BHTO was added to 100 parts by weight of crystalline ethylene propylene block copolymer powder with a melt flow rate of 0.3 S'/10 minutes and an ethylene content of 6.0%.
RGANOX 1010 0.3 parts by weight.

Calcium stearate 0.1 part by weight, copper damage inhibitor 0.
0.065 parts by weight of powdered peroxide consisting of a mixture of 6 parts by weight and highly dispersed silicic anhydride containing 40% by weight of 2,5-dimethyl-2,5-di(1-butylperoxy)hexane was dried. After blending, add high density polyethylene (grade name: 5) to 80 parts by weight of this powder.
5003B, manufactured by Showa Denko ■) was added thereto, and the mixture was blended again and pelletized using an extruder at a maximum temperature of 280°C to obtain a polypropylene composition for extrusion coating. The melt flow rate of this pellet was 2.9 r/10 min. The O2 measurement results are shown in Table 1.

Example A melt flow rate of 3.1 f/10 was prepared in the same manner as in Example 2, except that linear low-density polyethylene (grade name 1FjOH, manufactured by Mitsubishi Yuka) was used as the polyethylene.
Pellets of a polypropylene composition for extrusion coating were obtained.

The measurement results are shown in Table 1.

Comparative Example 1 Melt flow rate 3. OS'/I o min+: 100 parts by weight of crystalline ethylene-propylene block copolymer powder with r-CH L/7 content of 6.0 cm, 15 parts by weight of BHTo, a known additive, ■rganox 10
100,. After tri-blending 3 parts by weight, 0.1 parts by weight of calcium stearate, and 0.6 parts by weight of a copper damage inhibitor, the mixture was pelletized at a resin temperature of 250°C.

The measurement results are shown in Table 1.

Comparative Example 2 The blended powder product (80% by weight) of Comparative Example 1 was blended with 20% by weight of polyethylene (SB5003), and then pelletized at a maximum temperature of 250°C.

The measurement results are shown in Table 1.

Comparative Example: Polyethylene (F30H) was added to the blended powder product of Comparative Example 1 (80% by weight) at a maximum temperature of 280° C. after 20% by weight friending.

○: Good ×：Poor

Claims (2)

[Claims] (1) 60 to 95 parts by weight of heat-treated polypropylene obtained by heat treating polypropylene resin in the presence of peroxide and 5 to 40 parts by weight of polyethylene having a crystallinity of 25% or more as determined by X-ray analysis. A polypropylene composition for extrusion coating with improved moldability, which is obtained by mixing 100 parts by weight. (2) A resin mixture prepared by mixing 60 to 95 parts by weight of polypropylene resin and 5 to 40 parts by weight of polyethylene with a degree of crystallinity of 25% or more as determined by X-ray analysis so that the total of these parts is 100 parts by weight is mixed with peroxide. A polypropylene composition for extrusion coating with improved moldability obtained by heat treatment in the presence of a polypropylene resin.