CN102070841B - Polypropylene foam sheet prepared from composite foaming agent and production method thereof - Google Patents

Abstract

The invention relates to a polypropylene foam sheet prepared from a composite foaming agent and a production method thereof. The invention provides the polypropylene foam sheet. The polypropylene foam sheet comprises the following raw materials in part by weight: 100 parts of polypropylene resin, 0.1 to 3 parts of nucleating agent, 0.1 to 3 parts of antioxidant, 0.1 to 3 parts of cell stabilizer, and the composite foaming agent, wherein the composite foaming agent comprises the following components in part by weight: 1 to 10 parts of first component foaming agent and 0.5 to 5 parts of second component foaming agent. The invention also provides the production method of the polypropylene foam sheet. The polypropylene foam sheet provided by the invention has medium-low foaming power, and the product has high comprehensive evaluation of the foaming power, cell dimension distribution and mechanical property and is suitable for rigid bearing and thermoforming. The preparation method of the polypropylene foam sheet provided by the invention is characterized in that the production process is highly successive, stable, safe and environmentally-friendly, and is suitable for industrialized mass production.

Description

Adopt the polypropylene foam sheet material and the working method thereof of composite foamable agent

Technical field

The present invention relates to a kind of polypropylene foam sheet material and working method thereof that adopts composite foamable agent, belong to the high molecular foam material preparing technical field.

Background technology

The foam of polymers sheet material has obtained using widely in various industries and daily life owing to have advantages such as light weight, heat insulation, sound insulation, energy-absorbing, buffering.According to the expansion ratio of polymer foaming material, i.e. the ratio of polymeric matrix density and foam material density, the polymer foaming material can be divided into ultra-high magnifications (more than 40 times), high magnification (40-4 is doubly) and low range (below 4 times).Wherein, the polymer foaming sheet material of low range also has favorable rigidity and thermotolerance except the common characteristic with foam sheet, the very suitable occasions such as container package, automobile liner base material such as needing enough inflexible cups, bowl that are applied in.

But some purposes requires foam sheet to have higher thermotolerance, and the thermotolerance of common Vilaterm, PS and polyurethane foam is not high enough.PS and polyurethane foam product were difficult for recycling after working life in addition, and polyethylene does not have enough rigidity usually.

Vestolen PP 7052 (PP) resin has favorable rigidity, and higher heat-drawn wire, chemical-resistant and be easy to reclaim are suitable as the matrix resin of foam sheet very much.But use the expanded polypropylene bead can obtain having certain thermotolerance and inflexible polypropylene foamed sheet, but this polypropylene foam sheet material possibly not have mechanical properties such as sufficiently high tensile strength, resistance to impact shock and flexural strength under some occasion through after the compression molding.

Chinese patent CN1271125C discloses a kind of polypropylene expanded method; It is the acrylic resin microparticulate in a kind of autoclave of the dispersion medium that contains organo-peroxide; So that organo-peroxide decomposes the acrylic resin particulate is carried out surface-treated thereby heat this dispersion-s then, and use a kind of whipping agent to make the acrylic resin particulate of this non-crosslinked, surface-treated after the autoclave pressure release, obtain the technology of polypropylene foaming beads.But this explained hereafter cycle, length, complex process and cost were higher.

The nineties in last century, along with Basell and the Borealis company high melt strength, propylene that released one after another, the technology that adopts continuous process to produce polypropylene foam has had great breakthrough.U.S. Pat 6251319 discloses a kind of butane that uses and has prepared the method for polypropylene foamed sheet as whipping agent, and still, butane belongs to flammable explosive gas, in using and producing, all need special processing, so the cost of this polypropylene foamed plate is higher.

Chinese patent CN1118507C discloses a kind of method of making thermoformable polypropylene foam sheet.This method is used high melt strength, propylene, but the goods percentage of open area reach as high as 70% and abscess-size bigger, be unfavorable under some occasion, carrying out rigidity and carry.

Chinese patent CN1435315A discloses a kind of expanded polypropylene resin sheet that contains foaming layer, and the sheet material that this method is produced also contains the resin cortex of the solid layer that accounts for total thickness 20%.But, this method complex manufacturing, the runner that needs particular design and mouthful mould realize solid layer and foaming layer rapidly, bonding securely, to equipping and the having relatively high expectations of operant level.

Chinese patent CN101538387A discloses a kind of PP foam material and working method thereof; This method uses supercutical fluid as whipping agent, because the supercutical fluid state labile is difficult to use in and carries and metering; Therefore extrusion and foaming process is stable inadequately, is difficult to guarantee large-scale production.

Therefore, seeking a kind of novel PP foam material, to adapt to the large-scale production of continous-stable, is one of this area problem demanding prompt solution.

Summary of the invention

For solving the problems of the technologies described above, the object of the present invention is to provide a kind of adopt composite foamable agent technology in low expansion ratio, have the polypropylene foam sheet material and the working method thereof of good rigidity and suitable serialization scale prodn.

For achieving the above object, the present invention at first provides a kind of polypropylene foam sheet material, and it has following raw material and forms:

Acrylic resin, 100 weight parts; Nucleator, 0.1-3 weight part; Oxidation inhibitor, 0.1-3 weight part; Foaming stabilizer, 0.1-3 weight part; Composite foamable agent;

Wherein, composite foamable agent comprises first component whipping agent of 1-10 weight part and the second component whipping agent of 0.5-5 weight part.

In above-mentioned polypropylene foam sheet material, the total amount of the composite foamable agent that is adopted may be controlled to 2-18 weight part (preferred 2-10 weight part), and preferably, the first component whipping agent that is adopted can be for Liquid carbon dioxide etc.; The second component whipping agent that is adopted can be one or more the mixture in azo cpd, sulfonyl hydrazide compound and the Hydrocerol A etc., perhaps can be for containing one or more the mixture of polymer masterbatch in the above-mentioned whipping agent (being azo cpd, sulfonyl hydrazide compound and Hydrocerol A etc.).More preferably, the above-mentioned second component whipping agent can be Cellmic C 121,4, and the mixture of one or more in 4-disulfonyl hydrazide diphenyl ether and the Hydrocerol A etc. is perhaps for containing one or more the mixture of polymer masterbatch in the above-mentioned whipping agent.

In above-mentioned composite foamable agent, the first component whipping agent is a main foaming agent, is used for polyacrylic foaming, and the second component whipping agent can play the effect that improves cell density.Except above-mentioned two portions component; The composite foamable agent that the present invention adopted can also comprise the 3rd component whipping agent of 0.5-3 weight part; The 3rd component whipping agent can play the effect that improves the abscess-size size; And the 3rd component whipping agent can be one or more the mixture in water, ethanol, butane, pentane, methyl-formiate and the dme etc.

In polypropylene foam sheet material provided by the present invention; Preferably; The melt flow rate(MFR) of acrylic resin is 2-5g/10min, and acrylic resin can be the mixture of high melt strength, propylene or high melt strength, propylene and general purpose polypropylene; And when adopting the mixture of high melt strength, propylene and general purpose polypropylene, the part by weight of the two is 90: 10 to 50: 50.Wherein, the general purpose polypropylene that is adopted preferably can be isotatic polypropylene, atactic copolymerized polypropene and block polypropylene etc.

In polypropylene foam sheet material provided by the present invention; Nucleator is mainly used in the raising cell density; Its mechanism of action is different with the second component whipping agent; Preferably, the nucleator that is adopted can be one or more the mixture in talcum powder, lime carbonate, nano imvite, titanium oxide and the silicon-dioxide etc.

In polypropylene foam sheet material provided by the present invention; Oxidation inhibitor is mainly used in and prevents that Vestolen PP 7052 from adding the generation β degraded of being heated man-hour; Preferably, the oxidation inhibitor that is adopted can be four (3,5-di-t-butyl-4-hydroxyl) phenylpropionic acid pentaerythritol ester, three (2; The 4-di-tert-butyl-phenyl) mixture of one or more in phosphorous acid ester and β-hydroxy-aromatic compounds such as (3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid octadecanol ester.

In polypropylene foam sheet material provided by the present invention; Foaming stabilizer is mainly used in the intensity that improves cell wall; Prevent breaking of cell wall; Play the effect of stable bubble hole, preferably, the foaming stabilizer that is adopted is one or more mixtures in glycerol fatty acid ester class foaming stabilizer, propylene glycol fatty acid ester class foaming stabilizer and the isooctyl alcohol fatty acid ester foaming stabilizer etc.More preferably, the foaming stabilizer that is adopted is a glycerol fatty acid ester class foaming stabilizer, and glyceryl monostearate for example generally can be the compounds that the material esterification such as lipid acid and glycerine, glycol through containing C16-C18 obtains.

Polypropylene foam sheet material provided by the present invention can be to adopt above-mentioned raw material to prepare through continuous extrusion foaming.

The present invention also provides the working method of above-mentioned polypropylene foam sheet material, and it may further comprise the steps:

With acrylic resin, the second component chemical whipping agent, nucleator, oxidation inhibitor and foaming stabilizer uniform mixing, obtain mixture;

Mixture is carried out extruding pelletization on twin screw extruder, through forming foaming raw material after the 75-80 ℃ of oven dry 5-6h;

Above-mentioned foaming raw material is added continuous extrusion foaming use forcing machine; The mixture of the first component whipping agent or the first component whipping agent and the 3rd component whipping agent is injected forcing machine; After thorough mixing, cooling, foam shaping by extrusion obtains the polypropylene foam sheet material.

In the process of preparation polypropylene foam sheet material; The continuous extrusion foaming that is adopted can be the single screw rod in two rank-single screw rod series connection forcing machine, two rank twin screw-single screw rod series connection forcing machine or single-order single screw extrusion machine with forcing machine, and processing temperature may be controlled to 160-230 ℃.

When adding the mixture of the first component whipping agent or the first component whipping agent and the 3rd component whipping agent; Can carry out through the equipment of in extrusion foaming, being used always; Preferably can adopt high-precision foamed dose of metering system; Should be liquid specific, mainly form by the metering system of wet tank, one-level booster pump, secondary volume pump and mass rate control.When adding, the IR (injection speed) of the mixture of the first component whipping agent or the first component whipping agent and the 3rd component whipping agent may be controlled to 0.6-6kg/h.This blowing agent metering system can guarantee the accurate and stable conveying and the metering of whipping agent in process of production for a long time, and wherein, the topping-up pump that is adopted can be plunger compression pump or barrier film compression pump etc.

The mouth mould that in forcing machine, is adopted can be the annular or the sheet shape mouth mould of electrically heated temperature control or oil bath heating temperature control, and can be furnished with the foaming stabilizing deyice that is used to control the melt homogeneity at the rear portion of mouth mould.

Compare with prior art, technical scheme provided by the present invention has the following advantages:

Polypropylene foam sheet material provided by the present invention be a kind of in the polypropylene foam sheet material of low expansion ratio, and the expansion ratio of product, cell size distribution and mechanical property comprehensive evaluation are good, the suitable rigidity of carrying out is carried and thermoplastic shaping.The preparing method's of polypropylene foam sheet material provided by the present invention production process height continuous and stable, production process safety non-environmental-pollution are fit to commercial scale prodn.

Description of drawings

Following accompanying drawing only is intended to the present invention is done schematic illustration and explanation, not delimit the scope of the invention.Wherein:

Fig. 1 is the stereoscan photograph of embodiment 1 resulting polypropylene foam sheet material;

Fig. 2 is the stereoscan photograph of embodiment 2 resulting polypropylene foam sheet materials.

Embodiment

To understand in order technical characterictic of the present invention, purpose and beneficial effect being had more clearly, with reference to Figure of description technical scheme of the present invention is carried out following detailed description, but but can not be interpreted as qualification at present practical range of the present invention.

The polypropylene foam sheet material of employing composite foamable agent provided by the present invention can prepare according to following concrete working method:

1, with acrylic resin, nucleator, oxidation inhibitor and foaming stabilizer uniform mixing, obtain mixture, the raw material of each embodiment is formed as shown in table 1;

2, on twin screw extruder, the said mixture material is carried out extruding pelletization; The processing temperature in forcing machine 1 district to 6 district is respectively 180 ℃, 190 ℃, 210 ℃, 220 ℃, 210 ℃, 190 ℃; Head temperature is 180 ℃, through forming the special-purpose raw material of foaming after 80 ℃ of oven dry 6h;

3, in above-mentioned raw materials, add the second component whipping agent; And after mixing; Add the special-purpose forcing machine of continuous extrusion foaming; By the mixture injection forcing machine of high-precision foamed dose of metering system with the first component whipping agent or the first component whipping agent and the 3rd component whipping agent, through forcing machine thorough mixing, temperature control, wherein the temperature of forcing machine is respectively 180,185,190 ℃ of delivery areas; 195,200,195,190,185,180,175,170 ℃ of compression zones; 160,160,160,160 ℃ of homogenization zones; 158 ℃ of head temperatures.Via extrusion foaming sheet material special mould foam shaping by extrusion, the sheet width after the moulding is 400-1000mm.

Method according to GB1033-86 is carried out the apparent density that standard testing obtains the polypropylene foam sheet material, and then can calculate expansion ratio numerical value according to formula " expansion ratio=fluoropolymer resin density/foaming back foam apparent density "; It is disconnected that polypropylene foam is quenched through liquid nitrogen, utilizes ESEM (SEM) to observe section behind the section metal spraying, can calculate abscess-size and cell density, and concrete test result is as shown in table 1.

Table 1

Above-described specific embodiment; The object of the invention, technical scheme and beneficial effect have been carried out further explain, and institute it should be understood that the above is merely specific embodiment of the present invention; And be not used in qualification protection scope of the present invention; All within spirit of the present invention and principle, any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (6)

1. polypropylene foam sheet material, it has following raw material and forms:

Acrylic resin, 100 weight parts; Nucleator, 0.1-3 weight part; Oxidation inhibitor, 0.1-3 weight part; Foaming stabilizer, 0.1-3 weight part; Composite foamable agent;

Wherein, said composite foamable agent comprises first component whipping agent of 1-10 weight part and the second component whipping agent of 0.5-5 weight part; Wherein, the said first component whipping agent is a Liquid carbon dioxide;

The said second component whipping agent is one or more the mixture in azo cpd, sulfonyl hydrazide compound and the Hydrocerol A; Perhaps, the said second component whipping agent is one or more the mixture of polymer masterbatch that contains in azo cpd, sulfonyl hydrazide compound and the Hydrocerol A;

Said composite foamable agent also comprises the 3rd component whipping agent of 0.5-3 weight part, and said the 3rd component whipping agent is one or more the mixture in water, ethanol, butane, pentane, methyl-formiate and the dme;

And the working method of this polypropylene foam sheet material may further comprise the steps:

With acrylic resin, nucleator, oxidation inhibitor and foaming stabilizer uniform mixing, obtain mixture;

On twin screw extruder, the said mixture material is carried out extruding pelletization; The processing temperature in forcing machine 1 district to 6 district is respectively 180 ℃, 190 ℃, 210 ℃, 220 ℃, 210 ℃, 190 ℃; Head temperature is 180 ℃, through forming the special-purpose raw material of foaming after 80 ℃ of oven dry 6h;

In said foaming raw material, add the second component whipping agent; And after mixing; Add continuous extrusion foaming and use forcing machine; By high-precision foamed dose of metering system the mixture of the first component whipping agent and the 3rd component whipping agent is injected continuous extrusion foaming and use forcing machine, through forcing machine thorough mixing, temperature control, wherein the temperature of forcing machine is respectively 180,185,190 ℃ of delivery areas; 195,200,195,190,185,180,175,170 ℃ of compression zones; 160,160,160,160 ℃ of homogenization zones; 158 ℃ of head temperatures; Through foam sheet mouth mould foam shaping by extrusion, obtain said polypropylene foam sheet material.

2. polypropylene foam sheet material as claimed in claim 1; Wherein, The said second component whipping agent is a Cellmic C 121,4; The mixture of one or more in 4-disulfonyl hydrazide diphenyl ether and the Hydrocerol A, perhaps, the said second component whipping agent is one or more the mixture of polymer masterbatch that contains in the above-mentioned whipping agent.

3. polypropylene foam sheet material as claimed in claim 1, wherein, said nucleator is one or more the mixture in talcum powder, lime carbonate, nano imvite, titanium oxide and the silicon-dioxide.

4. polypropylene foam sheet material as claimed in claim 1; Wherein, Said oxidation inhibitor is four (3; 5-di-t-butyl-4-hydroxyl) mixture of one or more in phenylpropionic acid pentaerythritol ester, three (2, the 4-di-tert-butyl-phenyl) phosphorous acid ester and β-(3, the 5-di-tert-butyl-hydroxy phenyl) propionic acid octadecanol ester.

5. polypropylene foam sheet material as claimed in claim 1, wherein, said foaming stabilizer is one or more mixtures in glycerol fatty acid ester class foaming stabilizer, propylene glycol fatty acid ester class foaming stabilizer and the isooctyl alcohol fatty acid ester foaming stabilizer.

6. the working method of each described polypropylene foam sheet material of claim 1-5, it may further comprise the steps:

With acrylic resin, nucleator, oxidation inhibitor and foaming stabilizer uniform mixing, obtain mixture;

On twin screw extruder, said mixture is carried out extruding pelletization; The processing temperature in forcing machine 1 district to 6 district is respectively 180 ℃, 190 ℃, 210 ℃, 220 ℃, 210 ℃, 190 ℃; Head temperature is 180 ℃, through forming the special-purpose raw material of foaming after 80 ℃ of oven dry 6h;

In said foaming raw material, add the second component whipping agent; And after mixing; Add continuous extrusion foaming and use forcing machine; By high-precision foamed dose of metering system the mixture of the first component whipping agent and the 3rd component whipping agent is injected continuous extrusion foaming and use forcing machine, through forcing machine thorough mixing, temperature control, wherein the temperature of forcing machine is respectively 180,185,190 ℃ of delivery areas; 195,200,195,190,185,180,175,170 ℃ of compression zones; 160,160,160,160 ℃ of homogenization zones; 158 ℃ of head temperatures; Through foam sheet mouth mould foam shaping by extrusion, obtain said polypropylene foam sheet material.