CN102391570A - Extrusion foaming polypropylene particles with lower thermal molding temperature and preparation method thereof - Google Patents

Abstract

The invention discloses extrusion foaming polypropylene particles with lower thermal molding temperature, which comprises the following components in part by weight: 100 parts of polypropylene, 0.02-0.6 part of beta nucleating agent, 0-0.6 part of antioxidant, 0-2 parts of lubricating agent, 0-3 parts of foaming nucleating agent and 0-2 parts of coloring agent, wherein the polypropylene is high-melt-strength polypropylene and co-polypropylene. The invention further discloses a preparation method for the extrusion foaming polypropylene particles. The method is simple to operate, can be applied to continuous production, and is suitable for industrial production.

Description

Has EXTRUSION FOAMED PP bead of low hot-forming temperature and preparation method thereof

Technical field

The present invention relates to the high molecular foam material production technical field, be specifically related to a kind of EXTRUSION FOAMED PP bead and preparation method thereof with low hot-forming temperature.

Background technology

Porous plastics has advantages such as light weight, heat insulation, sound insulation, buffering, specific tenacity are high, cheap, therefore is used widely in fields such as packing business, industry, agricultural, transportation, war industry, space industry and daily necessities.The conventional foam plastics have polystyrene foamed (PS), polyethylene foamed (PE), expanded polypropylene (PP) and polyurathamc (PU) etc.

Compare with traditional foam PS, foaming PE, foaming PP has the advantage of many uniquenesses: the thermotolerance that (1) is good, foam PS are used down at 80 ℃ usually, and only ability 70-80 ℃ of foaming PE, and 120 ℃ of foaming PP abilities can be at life-time service under the hot environment; (2) excellent mechanical property, the modulus in flexure of PP be much larger than PE, so PP foamy static load ability is superior to the PE foam, and PP foamy impact property is superior to the PS foam; In addition, foaming PP also has significant thermal insulation, good chemical resistance, good stress cracking resistance.Based on above-mentioned advantage, the PP foam material especially has competitive power in the application of automotive industry and food packaging industry in the application of many industrial circles, can substitute existing P S foam and PE foam, and application prospect is boundless.

At present, the method for preparing polypropylene foam mainly contains extrusion molding, compression molding etc.Wherein, extrusion molding can be produced continuously, but generally can only be used for the production of products such as sheet material, sheet material, is difficult to prepare complex-shaped product.And the mold pressing rule is expanded bead to be put into the mould of specified shape, utilizes steam heating to make then and is welding together the formation goods between the expanded bead.Therefore, compression molding is used for preparing complex-shaped goods widely.In compression molding, it is particularly important that the preparation of expanded bead seems.Expanded bead can be with extrusion molding or the preparation of still formula method.Prepare in the process of foam plastic product in compression molding, the steam that needs to feed certain pressure is welded together the expanded bead surface.Vapor pressure is high, and equipment cost and energy consumption will sharply rise.In order to reduce production costs, be necessary to reduce the fusion temp of PP expanded bead, (hot-forming temperature).

The method of reduction expanded polypropylene bead hot-forming temperature commonly used mainly contains following two kinds at present:

1. with the blend of random copolymerization PP, block copolymerization PP or they and the linear PP base-material as expanded bead, wherein comonomer can be ethene, 1-butylene, 1-amylene, 1-hexene etc.Can reduce the PP fusing point through copolymerization, thereby reach the purpose that reduces PP expanded bead hot-forming temperature.With Japanese Patent JP 59-91502 is example, and it is base-material with the ethylene-propylene random copolymer, and the therein ethylene weight content is 3.5wt%, and this base-material utilizes the moulding vapor pressure of the expanded bead that still formula foaming obtains can be low to moderate 0.3MPa (134 ℃ of temperature).Chinese patent ZL02803474.0 has adopted the non-cross-linking PP random copolymers of 138～140 ℃ of fusing points as starting material.Because copolymerization has destroyed the molecular structure of PP, make that the heat resisting temperature of foaming product reduces, the mechanical property variation, be inappropriate for the high performance polypropylene foaming beads of preparation.

2. utilize organo-peroxide to handle the expanded bead surface.The Japan JSP ZL01819174.6 of house journal; ZL 02826640.4, and ZL 200410061513.X, ZL 200410063190.8 have described a kind of method of utilizing still formula method to produce polypropylene foaming beads: in this method; Coat the organo-peroxide of one deck decomposition temperature between Vestolen PP 7052 fusing point and vicat softening point temperature on the matrix resin surface earlier; And it is decomposed more than 50%, and make the surface produce to a certain degree crosslinked, foam then.Present two melting peaks (cryogenic melting peak heat enthalpy value is less than 86% of high-temperature fusion peak heat enthalpy value) on the DSC curve of gained expanded bead.The homopolymerization PP expanded bead moulding vapor pressure that utilizes this method to obtain can be low to moderate 0.36MPa (140 ℃ of temperature).Adopt organo-peroxide to handle the method on expanded bead surface, meeting residual peroxide and degradation production thereof in foaming product can not be applied to the field that hygienic requirements is arranged with Food Contact; And superoxide and degradation production thereof are influential to the work-ing life of goods; Production technique is comparatively complicated in addition, in extrusion and foaming process, is difficult to realize.

Summary of the invention

The invention provides a kind of EXTRUSION FOAMED PP bead with low hot-forming temperature.

The present invention also provides a kind of preparation method with EXTRUSION FOAMED PP bead of low hot-forming temperature, but this method continuous production and environmentally friendly is suitable for suitability for industrialized production.

A kind of EXTRUSION FOAMED PP bead with low hot-forming temperature comprises the Vestolen PP 7052 of 100 weight parts and the beta nucleater of 0.02 weight part-0.6 weight part.

Described Vestolen PP 7052 is selected high melt strength, propylene and COPP for use, and described COPP comprises atactic copolymerized polypropene or block copolymerization polypropylene etc.

The weight percentage of COPP is preferably 10%-60% in described high melt strength, propylene and the COPP, further is preferably 10%-30%.

Described high melt strength, propylene is selected for use: utilize Gottfert " Rheotens " melt strength tester to measure down at 190 ℃, melt strength values is at the Vestolen PP 7052 of 5cN-50cN.

Described Vestolen PP 7052 all can be selected the commercially available prod for use.

According to the demand of different field, described EXTRUSION FOAMED PP bead further comprises the oxidation inhibitor of 0-0.6 weight part, the lubricant of 0-2 weight part, the foaming nucleation agent of 0-3 weight part and the tinting material of 0-2 weight part.

Described beta nucleater can be selected the condensed-nuclei aromatics class for use, like quinacridone etc.; Organic carboxyl acid and its esters are like pimelic acid/calcium stearate mixture, calcium suberate etc.; Replace or unsubstituted aromatic amides class, like dicyclohexyl terephthalamide, naphthalene two Cyclohexamides etc.; The rare earth class nucleator; The mineral-type nucleator like in Calucium Silicate powder, the lime carbonate etc. one or more, can be selected the commercially available prod for use.Described beta nucleater consumption is preferably 0.05 weight part-0.6 weight part.

The use of described beta nucleater; The preferred beta nucleater masterbatch that adopts; Described beta nucleater masterbatch is made up of the raw material of following part by weight: beta nucleater: Vestolen PP 7052=1: 2-9, further be preferably 1: 9, and the mixture extruding pelletization of this ratio is made the beta nucleater masterbatch.The used preferred high melt strength, propylene of Vestolen PP 7052 in the described beta nucleater masterbatch.

In the preferred antioxidant 1010 of described oxidation inhibitor, the oxidation inhibitor 168 etc. one or both can be selected the commercially available prod for use.Add oxidation inhibitor and can improve polyacrylic heat oxygen aging resistance ability.

The ester compound of long-chain fat family base, in the paraffin one or more are arranged on preferred Triple Pressed Stearic Acid of described lubricant, stearate, the molecular chain, can select the commercially available prod for use.Can select Triple Pressed Stearic Acid and metallic salt thereof for use, like Triple Pressed Stearic Acid, calcium stearate, barium stearate, Magnesium Stearate, Zinic stearas etc.; The ester compound that long-chain fat family base is arranged on the molecular chain is like glyceryl monostearate, Tristearoylglycerol etc.; Amides is like amine hydroxybenzene, stearic amide, ethylene bis stearic acid amide etc.; In the paraffin one or more.Add lubricant and help polyacrylic extrusion moulding.

In described foaming nucleation agent preferably talc powder, Sodium Benzoate, lime carbonate, titanium oxide, polynite, the silicon-dioxide one or more can be selected the commercially available prod for use.The agent of adding foaming nucleation helps the nucleation of Vestolen PP 7052 abscess.

Described tinting material is selected one or more in pigment dyestuff and the mineral dye for use, can select the commercially available prod for use.Add tinting material and can obtain required color, with dealing with various requirements.

A kind of preparation method with EXTRUSION FOAMED PP bead of low hot-forming temperature comprises step:

Get the Vestolen PP 7052 of 100 weight parts, the beta nucleater of 0.02 weight part-0.6 weight part, the oxidation inhibitor of 0-0.6 weight part, the lubricant of 0-2 weight part, the foaming nucleation agent of 0-3 weight part and the tinting material of 0-2 weight part; Mix the back and drop into forcing machine; And in forcing machine, inject supercritical co or overcritical nitrogen; The head pressure of forcing machine is 9MPa-25MPa, and head temperature is 140 ℃-170 ℃, per os mould foaming back underwater cutpellet; The water temperature of underwater cutpellet is 40 ℃-70 ℃, makes the EXTRUSION FOAMED PP bead with low hot-forming temperature.

In order to reach better invention effect, the preparation method of described EXTRUSION FOAMED PP bead preferably includes step: the beta nucleater with polypropylene segment and 0.02 weight part-0.6 weight part mixes and extruding pelletization in advance, makes the beta nucleater masterbatch; Again with beta nucleater masterbatch and remaining Vestolen PP 7052 and the oxidation inhibitor of 0-0.6 weight part, the lubricant of 0-2 weight part, the foaming nucleation agent of 0-3 weight part and the tinting material of 0-2 weight part; Mix the back and drop into forcing machine; And in forcing machine, inject supercritical co or overcritical nitrogen; The head pressure of forcing machine is 9MPa-25MPa, and head temperature is 140 ℃-170 ℃, per os mould foaming back underwater cutpellet; The water temperature of underwater cutpellet is 40 ℃-70 ℃, makes the EXTRUSION FOAMED PP bead with low hot-forming temperature;

Wherein, beta nucleater and polyacrylic weight ratio are 1 in the described beta nucleater masterbatch: 2-9 further is preferably 1: 9.

Perhaps, the preparation method of described EXTRUSION FOAMED PP bead preferably includes step: the beta nucleater with part high melt strength, propylene and 0.02 weight part-0.6 weight part mixes and extruding pelletization in advance, makes the beta nucleater masterbatch; Again with beta nucleater masterbatch and remaining Vestolen PP 7052 and the oxidation inhibitor of 0-0.6 weight part, the lubricant of 0-2 weight part, the foaming nucleation agent of 0-3 weight part and the tinting material of 0-2 weight part; Mix the back and drop into forcing machine; And in forcing machine, inject supercritical co or overcritical nitrogen; The head pressure of forcing machine is 9MPa-25MPa, and head temperature is 140 ℃-170 ℃, per os mould foaming back underwater cutpellet; The water temperature of underwater cutpellet is 40 ℃-70 ℃, makes the EXTRUSION FOAMED PP bead with low hot-forming temperature;

Wherein, the weight ratio of beta nucleater and high melt strength, propylene is 1 in the described beta nucleater masterbatch: 2-9.

With respect to 100 weight part Vestolen PP 7052, the consumption of described supercritical co or overcritical nitrogen is preferably 4 weight parts-10 weight part.

The foaming density of described expanded polypropylene bead generally can reach 0.025g/cm ³-0.09g/cm ³

Performance test of the present invention:

Foaming density p according to the standard A STM D792-08 of U.S. test materials association test expanded bead _f

Foaming density calculation formula is:

ρ _f＝a/(a+w-b)

A: the aerial quality of foaming sample, w makes the quality of the foaming water-immersed metal cap of sample in water, and b is the quality of foaming sample in water.

The expansion ratio calculation formula:

$n=\frac{{\mathrm{\ρ}}_P}{{\mathrm{\ρ}}_f}$

N: expansion ratio, ρ _P: the density of matrix resin, ρ _f: the density of expanded bead.

Utilize differential scanning calorimeter (DSC) to measure the thermal property of expanded bead.Test condition: take by weighing 5mg left and right sides sample, under the nitrogen protection condition, be warmed up to 200 ℃ from 40 ℃ of conditions with 10 ℃/min.

The present invention has following advantage:

(1) the present invention utilizes extrusion molding to prepare polypropylene foaming beads, the control foaming process conditions, and the expanded bead of the controllable density that can obtain foaming has higher production efficiency.

(2) the resulting polypropylene foaming beads of the present invention has two or more melting peaks.Wherein the melting peak of lesser temps is the brilliant melting peak of β, and the melting peak of comparatively high temps is the brilliant melting peak of α.The welding of expanded polypropylene bead mainly relies on the brilliant fusion of β, can realize at a lower temperature that in the fusion process of expanded polypropylene bead, part β crystalline substance changes the α crystalline substance into; What the α crystalline substance had then guaranteed the expanded polypropylene bead has higher mechanical strength and a heat-drawn wire.

Description of drawings

The DSC curve of the expanded polypropylene bead that Fig. 1 makes for embodiment 1;

The DSC curve of the expanded polypropylene bead that Fig. 2 makes for Comparative Examples 1;

Embodiment

Through embodiment the present invention is specifically described below, embodiment just is used for the present invention is further specified, but not to the restriction of protection domain of the present invention.

The preparation of beta nucleater masterbatch: will contain 10 kilograms of beta nucleater (TMB-5; The substituted aroma amides, Shanxi chemical research institute) and 90 kilograms of high melt strength, propylenes (RS1684, Basell companies; Utilize Gottfert " Rheotens " melt strength tester to measure down at 190 ℃; Its melt strength values is 5cN) mix and then in twin screw extruder, extrude screw speed 200rpm, 200 ℃ of temperature.Use as the beta nucleater masterbatch after the extruding pelletization drying.The beta nucleater masterbatch that uses among this patent embodiment all for this reason legal system be equipped with.

Embodiment 1:

With 4 kilograms of beta nucleater masterbatch, 66.4 kilograms of high melt strength, propylenes (RS1684, Basell company), 30 kilograms of block copolymerization polypropylenes (K8303, Yanshan Petrochemical company), 168,0.2 kilogram of antioxidant 1010 of 0.1 kilogram of oxidation inhibitor; Put into the forcing machine extrusion foaming after mixing, can add materials continuously, carry out continuous production according to the above-mentioned raw materials ratio; The extruded velocity of material is controlled at per hour extrudes 40 kilograms; The injection speed of supercritical co is controlled at per hour injects 3 kilograms, head pressure 17MPa, 160 ℃ of head temperatures; The underwater pelletizer water temperature is controlled at 60 ℃, obtains expansion ratio and be 30 times expanded polypropylene bead.The DSC curve of this expanded polypropylene bead is seen Fig. 1.

The expanded polypropylene bead that obtains is put into the thermoforming machine moulding, vapor pressure 0.45MPa (148 ℃ of fusion temps), the product surface that obtains is smooth, and bonding is very firm, seamless between the expanded bead.

Embodiment 2:

With 6 kilograms of beta nucleater masterbatch, 44.6 kilograms of high melt strength, propylenes (RS1684, Basell company), 50 kilograms of block copolymerization polypropylenes (K8303, Yanshan Petrochemical company), 168,0.2 kilogram of antioxidant 1010 of 0.1 kilogram of oxidation inhibitor; Put into the forcing machine extrusion foaming after mixing, can add materials continuously, carry out continuous production according to the above-mentioned raw materials ratio; The extruded velocity of material is controlled at per hour extrudes 40 kilograms; The injection speed of supercritical co is controlled at per hour injects 2.8 kilograms, head pressure 14MPa, 170 ℃ of head temperatures; The underwater pelletizer water temperature is controlled at 40 ℃, obtains expansion ratio and be 24 times expanded polypropylene bead.

The expanded polypropylene bead that obtains is put into the thermoforming machine moulding, vapor pressure 0.47MPa (150 ℃ of fusion temps), the product surface that obtains is smooth, and bonding is firm between the expanded bead, and is seamless.

Embodiment 3:

With 4 kilograms of beta nucleater masterbatch, 66.4 kilograms of high melt strength, propylene (RS1684; Basell company), 30 kilograms of block copolymerization polypropylenes (K8303, Yanshan Petrochemical company), 168,0.2 kilogram of antioxidant 1010 of 0.1 kilogram of oxidation inhibitor, 1 kilogram of calcium stearate, put into the forcing machine extrusion foaming after mixing; Can add materials continuously according to the above-mentioned raw materials ratio; Carry out continuous production, the extruded velocity of material is controlled at per hour extrudes 40 kilograms, and the injection speed of supercritical co is controlled at per hour injects 2.8 kilograms; Head pressure 15MPa; 150 ℃ of head temperatures, the underwater pelletizer water temperature is controlled at 60 ℃, obtains expansion ratio and be 23 times expanded polypropylene bead.

The expanded polypropylene bead that obtains is put into the thermoforming machine moulding, vapor pressure 0.45MPa (148 ℃ of fusion temps), the product surface that obtains is smooth, and bonding is firm between the expanded bead, and is seamless.

Embodiment 4:

With 4 kilograms of beta nucleater masterbatch, 66.4 kilograms of high melt strength, propylene (RS1684; Basell company), 30 kilograms of block copolymerization polypropylenes (K8303, Yanshan Petrochemical company), 168,0.2 kilogram of antioxidant 1010 of 0.1 kilogram of oxidation inhibitor, 1 kilogram of calcium stearate, 1 kilogram of black masterbatch, put into the forcing machine extrusion foaming after mixing; Can add materials continuously according to the above-mentioned raw materials ratio; Carry out continuous production, the extruded velocity of material is controlled at per hour extrudes 40 kilograms, and the injection speed of supercritical co is controlled at per hour injects 3 kilograms; Head pressure 15MPa; 160 ℃ of head temperatures, the underwater pelletizer water temperature is controlled at 60 ℃, obtains expansion ratio and be 26 times expanded polypropylene bead.

The expanded polypropylene bead that obtains is put into the thermoforming machine moulding, vapor pressure 0.45MPa (148 ℃ of fusion temps), the product surface that obtains is smooth, and bonding is firm between the expanded bead, and is seamless.

Embodiment 5:

With 4 kilograms of beta nucleater masterbatch, 66.4 kilograms of high melt strength, propylene (RS1684; Basell company), 30 kilograms of block copolymerization polypropylenes (K8303, Yanshan Petrochemical company), 168,0.2 kilogram of antioxidant 1010 of 0.1 kilogram of oxidation inhibitor, 1 kilogram of black masterbatch, 1 kilogram of calcium stearate, 500 gram talcum powder, put into the forcing machine extrusion foaming after mixing; Can add materials continuously according to the above-mentioned raw materials ratio; Carry out continuous production, the extruded velocity of material is controlled at per hour extrudes 40 kilograms, and the injection speed of supercritical co is controlled at per hour injects 3 kilograms; Head pressure 17MPa; 160 ℃ of head temperatures, the underwater pelletizer water temperature is controlled at 60 ℃, obtains expansion ratio and be 27 times black expanded polypropylene bead.

The expanded polypropylene bead that obtains is put into the thermoforming machine moulding, vapor pressure 0.47MPa (150 ℃ of fusion temps), the product surface that obtains is smooth, and bonding is firm between the expanded bead, and is seamless.

Comparative Examples 1: do not add the preparation and the thermoforming thereof of the polypropylene foaming beads of beta nucleater

With 70 kilograms of high melt strength, propylenes (RS1684, Basell company), 30 kilograms of block copolymerization polypropylenes (K8303, Yanshan Petrochemical company), 168,0.2 kilogram of antioxidant 1010 of 0.1 kilogram of oxidation inhibitor; Put into the forcing machine extrusion foaming after mixing, can add materials continuously, carry out continuous production according to the above-mentioned raw materials ratio; The extruded velocity of material is controlled at per hour extrudes 40 kilograms; The injection speed of supercritical co is controlled at per hour injects 3 kilograms, head pressure 17MPa, 160 ℃ of head temperatures; The underwater pelletizer water temperature is controlled at 60 ℃, obtains expansion ratio and be 30 times expanded polypropylene bead.This expanded polypropylene bead DSC curve is seen Fig. 2.

The expanded polypropylene bead that obtains is put into the thermoforming machine moulding, vapor pressure 0.62MPa (160 ℃ of fusion temps), the product surface that obtains is smooth, and bonding is firm between the expanded bead, and is seamless.

Claims (10)

1. the EXTRUSION FOAMED PP bead with low hot-forming temperature comprises the Vestolen PP 7052 of 100 weight parts, the beta nucleater of 0.02 weight part-0.6 weight part, the oxidation inhibitor of 0-0.6 weight part, the lubricant of 0-2 weight part, the foaming nucleation agent of 0-3 weight part and the tinting material of 0-2 weight part;

Described Vestolen PP 7052 is high melt strength, propylene and COPP.

2. the EXTRUSION FOAMED PP bead with low hot-forming temperature according to claim 1; It is characterized in that; Described high melt strength, propylene is meant: utilize Gottfert " Rheotens " melt strength tester to measure down at 190 ℃, melt strength values is at the Vestolen PP 7052 of 5cN-50cN.

3. the EXTRUSION FOAMED PP bead with low hot-forming temperature according to claim 1 is characterized in that the weight percentage of COPP is 10%-60% in the described Vestolen PP 7052.

4. the EXTRUSION FOAMED PP bead with low hot-forming temperature according to claim 1; It is characterized in that described beta nucleater is one or more in condensed-nuclei aromatics class, organic carboxyl acid, organic carboxylate, replacement or unsubstituted aromatic amides class, rare earth nucleator, the inorganic nucleator.

5. the EXTRUSION FOAMED PP bead with low hot-forming temperature according to claim 1 is characterized in that described oxidation inhibitor is one or both in antioxidant 1010, the oxidation inhibitor 168.

6. the EXTRUSION FOAMED PP bead with low hot-forming temperature according to claim 1; It is characterized in that described lubricant is that the ester compound of long-chain fat family base, in the paraffin one or more are arranged on Triple Pressed Stearic Acid, stearate, the molecular chain;

Perhaps, described tinting material is one or more in pigment dyestuff, the mineral dye.

7. the EXTRUSION FOAMED PP bead with low hot-forming temperature according to claim 1 is characterized in that described foaming nucleation agent is one or both in talcum powder, Sodium Benzoate, lime carbonate, titanium oxide, polynite, the silicon-dioxide.

8. according to each described a kind of preparation method of claim 1-7, comprise step with EXTRUSION FOAMED PP bead of low hot-forming temperature:

Get the Vestolen PP 7052 of 100 weight parts, the beta nucleater of 0.02 weight part-0.6 weight part, the oxidation inhibitor of 0-0.6 weight part, the lubricant of 0-2 weight part, the foaming nucleation agent of 0-3 weight part and the tinting material of 0-2 weight part; Mix the back and drop into forcing machine; And in forcing machine, inject supercritical co or overcritical nitrogen; The head pressure of forcing machine is 9MPa-25MPa, and head temperature is 140 ℃-170 ℃, per os mould foaming back underwater cutpellet; The water temperature of underwater cutpellet is 40 ℃-70 ℃, makes the EXTRUSION FOAMED PP bead with low hot-forming temperature.

9. according to each described a kind of preparation method of claim 1-7, comprise step with EXTRUSION FOAMED PP bead of low hot-forming temperature:

Beta nucleater with polypropylene segment and 0.02 weight part-0.6 weight part mixes and extruding pelletization in advance, makes the beta nucleater masterbatch; Again with beta nucleater masterbatch and remaining Vestolen PP 7052 and the oxidation inhibitor of 0-0.6 weight part, the lubricant of 0-2 weight part, the foaming nucleation agent of 0-3 weight part and the tinting material of 0-2 weight part; Mix the back and drop into forcing machine; And in forcing machine, inject supercritical co or overcritical nitrogen; The head pressure of forcing machine is 9MPa-25MPa, and head temperature is 140 ℃-170 ℃, per os mould foaming back underwater cutpellet; The water temperature of underwater cutpellet is 40 ℃-70 ℃, makes the EXTRUSION FOAMED PP bead with low hot-forming temperature;

Wherein, beta nucleater and polyacrylic weight ratio are 1 in the described beta nucleater masterbatch: 2-9.

10. according to each described a kind of preparation method of claim 1-7, comprise step with EXTRUSION FOAMED PP bead of low hot-forming temperature:

Beta nucleater with part high melt strength, propylene and 0.02 weight part-0.6 weight part mixes and extruding pelletization in advance, makes the beta nucleater masterbatch; Again with beta nucleater masterbatch and remaining Vestolen PP 7052 and the oxidation inhibitor of 0-0.6 weight part, the lubricant of 0-2 weight part, the foaming nucleation agent of 0-3 weight part and the tinting material of 0-2 weight part; Mix the back and drop into forcing machine; And in forcing machine, inject supercritical co or overcritical nitrogen; The head pressure of forcing machine is 9MPa-25MPa, and head temperature is 140 ℃-170 ℃, per os mould foaming back underwater cutpellet; The water temperature of underwater cutpellet is 40 ℃-70 ℃, makes the EXTRUSION FOAMED PP bead with low hot-forming temperature;

Wherein, the weight ratio of beta nucleater and high melt strength, propylene is 1 in the described beta nucleater masterbatch: 2-9.