Polystyrene compositions, polystyrene particles and polystyrene free foams suitable for free foaming

Abstract

The present application relates to the technical field of high polymer materials, and discloses a polystyrene composition suitable for free foaming, polystyrene particles and a polystyrene free foaming body. The polystyrene composition contains rubber, a thermoplastic resin and modified polystyrene, wherein the weight ratio of the content of the modified polystyrene and the thermoplastic resin is less than or equal to 1; and the content of the rubber is less than 250 parts by weight relative to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene; the modified polystyrene comprises a polyconjugated diene-styrene graft structure; and the content of the polyconjugated diene-styrene graft structure in the modified polystyrene is more than 100 ppm. The polystyrene composition and the polystyrene particles formed therefrom can effectively avoid the migration phenomenon of polystyrene molecules and thermoplastic resin during free foaming molding, and successfully foam to obtain a polystyrene free foaming body with excellent foaming performance and physical properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular material, in particular to a polystyrene composition suitable for free foaming, polystyrene particles and polystyrene free foams. BACKGROUND

[0002] Thermoplastic resin foaming materials have the advantages of low density, high specific strength, good thermal stability, excellent impact resistance, green environmental protection of raw materials and process, easy recycling and utilization, etc., and can be used as functional materials such as cushioning, shock absorption, sound insulation and heat insulation. At present, the common thermoplastic foaming materials can be mainly divided into four types according to different processing technologies, i.e. autoclave foaming, mold foaming, extrusion foaming and injection foaming. The first three foaming processes have the characteristics of wide foaming ratio (3-60 times), thin cell wall, continuous honeycomb-like cell structure and free growth during foaming without the limitation of mold, and are therefore also called free foaming.

[0003] Polypropylene, polyethylene, nylon and polyester all belong to crystalline resins, so during the cooling process of free foaming, cell formation and melt crystallization are two processes that affect each other and compete with each other. Too low crystallinity can easily lead to cell merging and even collapse, but too high crystallinity can also affect the final foaming ratio.

[0004] Polystyrene is a thermoplastic non-crystalline resin, which has the characteristics of hard quality, good transparency, rigidity, electrical insulation, low moisture absorption, low price, easy dyeing, easy processing, and thermal conductivity coefficient not changing with temperature. Due to the characteristics of polystyrene amorphous resin, there are attempts to blend polystyrene with crystalline thermoplastic resins to regulate its foaming performance.

[0005] However, the existing polystyrene and crystalline thermoplastic resin blend is still difficult to obtain a free foaming body with excellent foaming performance and physical properties through free foaming process, and therefore, there is still a problem in the field of thermoplastic resin free foaming preparation that it is difficult to free foam the thermoplastic resin composition containing polystyrene to obtain a free foaming body with excellent foaming structure. SUMMARY

[0006] The purpose of the present application is to overcome the above-mentioned problem that the existing polystyrene and thermoplastic resin blend is difficult to obtain a free foaming body with excellent cell quality and physical properties, and to provide a polystyrene composition suitable for free foaming, polystyrene particles and the like. The polystyrene composition and the polystyrene particles formed therefrom can effectively avoid the migration phenomenon of polystyrene molecules and thermoplastic resins during free foaming molding, thereby obtaining higher melt strength, and thus a polystyrene free foaming body with good foaming performance and excellent physical properties can be obtained by free foaming.

[0007] To achieve the above object, the present application provides a polystyrene composition for free foaming, which contains rubber, a thermoplastic resin and modified polystyrene, wherein the weight ratio of the content of the modified polystyrene and the thermoplastic resin is 1 or less; and the content of the rubber is less than 250 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene; the modified polystyrene comprises a polyconjugated diene-styrene graft structure; and the content of the polyconjugated diene-styrene graft structure in the modified polystyrene is 100 ppm or more.

[0008] The present application provides a polystyrene composition for free foaming, which contains rubber, a thermoplastic resin and modified polystyrene, wherein the weight ratio of the content of the modified polystyrene and the thermoplastic resin is 1 or less; and the content of the rubber is less than 250 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene; the modified polystyrene comprises a polyconjugated diene-styrene graft structure; and the content of the polyconjugated diene-styrene graft structure in the modified polystyrene is 100 ppm or more.

[0009] The present application provides a polystyrene composition for free foaming, which contains rubber, a thermoplastic resin and modified polystyrene, wherein the weight ratio of the content of the modified polystyrene and the thermoplastic resin is 1 or less; and the content of the rubber is less than 250 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene; the modified polystyrene comprises a polyconjugated diene-styrene graft structure; and the content of the polyconjugated diene-styrene graft structure in the modified polystyrene is 100 ppm or more.

[0010] The present application provides a polystyrene composition for free foaming, which contains rubber, a thermoplastic resin and modified polystyrene, wherein the weight ratio of the content of the modified polystyrene and the thermoplastic resin is 1 or less; and the content of the rubber is less than 250 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene; the modified polystyrene comprises a polyconjugated diene-styrene graft structure; and the content of the polyconjugated diene-styrene graft structure in the modified polystyrene is 100 ppm or more.

[0011] The present application provides a polystyrene composition for free foaming, which contains rubber, a thermoplastic resin and modified polystyrene, wherein the weight ratio of the content of the modified polystyrene and the thermoplastic resin is 1 or less; and the content of the rubber is less than 250 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene; the modified polystyrene comprises a polyconjugated diene-styrene graft structure; and the content of the polyconjugated diene-styrene graft structure in the modified polystyrene is 100 ppm or more.

[0012] The present application provides a polystyrene composition for free foaming, which contains rubber, a thermoplastic resin and modified polystyrene, wherein the weight ratio of the content of the modified polystyrene and the thermoplastic resin is 1 or less; and the content of the rubber is less than 250 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene; the modified polystyrene comprises a polyconjugated diene-styrene graft structure; and the content of the polyconjugated diene-styrene graft structure in the modified polystyrene is 100 ppm or more.

[0013] The present application provides a polystyrene composition for free foaming, which contains rubber, a thermoplastic resin and modified polystyrene, wherein the weight ratio of the content of the modified polystyrene and the thermoplastic resin is 1 or less; and the content of the rubber is less than 250 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene; the modified polystyrene comprises a polyconjugated diene-styrene graft structure; and the content of the polyconjugated diene-styrene graft structure in the modified polystyrene is 100 ppm or more.

[0014] Compared with the prior art, the present application has the following advantages:

[0015] 1) The polystyrene composition provided by the present application forms a polymer particle material, which has more uniform distribution of surface layer and central part.

[0016] 2) The polystyrene composition provided by the present application can be used to obtain a lower apparent density, and at the same time, has higher mechanical properties and thermal insulation performance. Therefore, it has excellent application potential in the field of lightweight manufacturing.

[0017] 3) The polystyrene free foaming molding body of the present application can be prepared by using various existing free foaming processes, and different process methods and different types of foaming agents can be used to prepare free foaming molding bodies with different properties according to the needs of downstream applications. DETAILED DESCRIPTION

[0018] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not critical to the present application. Any numerical value, however, can be expressed as a range to include any and all subranges therebetween. The ranges and individual points within those ranges are intended to be included herein. Any reference to a number of points is intended to include all points within the range, unless the context clearly indicates otherwise.

[0019] In one aspect, the present application provides a polystyrene composition suitable for free foaming, which comprises rubber, thermoplastic resin and modified polystyrene, wherein the weight ratio of the content of the modified polystyrene and the thermoplastic resin is 1 or less; and the content of the rubber is less than 250 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene; the modified polystyrene comprises a poly-conjugated diene-styrene graft structure; and the content of the poly-conjugated diene-styrene graft structure in the modified polystyrene is 100 ppm or more.

[0020] The inventors of the present application have found that, due to the non-uniformity of the flow field shear rate distribution during processing, migration occurs in the polystyrene and crystalline thermoplastic resin blend during foaming molding. That is, under the molding conditions, due to the difference in viscosity, the high-viscosity component in the blend migrates to the center and the low-viscosity component migrates to the surface in the direction perpendicular to the flow direction. This migration behavior has a great influence on the structure of the final foaming product.

[0021] In the present application, the modified polystyrene described above has a poly-conjugated diene-styrene graft structure, which is a polystyrene with long branches grafted on the poly-conjugated diene rubber with the poly-conjugated diene rubber microparticles as the center. The modified polystyrene can be well compatible with the thermoplastic resin and the rubber, and can avoid the migration of different components to different directions under the free foaming molding process conditions, so as to obtain polystyrene particles with more uniform distribution in the surface layer and the center, which is particularly suitable for the preparation of free foaming bodies.

[0022] According to the present application, preferably, the content of polyconjugated diene-styrene graft structure in the modified polystyrene is 100-12000 ppm (for example, it can be 200 ppm, 300 ppm, 400 ppm, 500 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm, 1000 ppm, 1100 ppm, 1200 ppm, 1300 ppm, 1400 ppm, 1500 ppm, 1600 ppm, 1700 ppm, 1800 ppm, 2000 ppm, 3000 ppm, 4000 ppm, 5000 ppm and a range formed by any two of the above values and values within the range), preferably 120-6000 ppm, preferably 700-1800 ppm, more preferably 1100-1600 ppm.

[0023] According to the present application, preferably, the melt strength of the modified polystyrene at 210°C is 0.18-0.8 N (for example, it can be 0.18 N, 0.2 N, 0.25 N, 0.3 N, 0.35 N, 0.4 N, 0.45 N, 0.5 N, 0.55 N, 0.6 N, 0.65 N, 0.7 N, 0.75 N, 0.8 N and a range formed by any two of the above values and values within the range). The modified polystyrene meeting the above range has more excellent compatibility with thermoplastic resins, rubber phases.

[0024] According to the present application, preferably, the gloss of the modified polystyrene at 60° is 80-100% (for example, it can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100% and a range formed by any two of the above values and values within the range). The gloss is determined according to the method in GB / T 8807-1988.

[0025] According to the present application, preferably, the light transmittance of the modified polystyrene at a thickness of 2 mm is 60-94% (for example, it can be 60%, 62%, 65%, 68%, 70%, 72%, 75%, 78%, 80%, 82%, 85%, 88%, 90%, 92%, 94% and a range formed by any two of the above values and values within the range). The light transmittance is determined according to the method in GB / T 2410-2008.

[0026] According to the present application, preferably, the Charpy notched impact strength of the modified polystyrene is 20-45 kJ / m 2 (for example, it can be 20 kJ / m 2 , 23 kJ / m 2 , 25 kJ / m2 , 28 kJ / m 2 , 30 kJ / m 2 , 32 kJ / m 2 , 35 kJ / m 2 , 38 kJ / m 2 , 40 kJ / m 2 , 43 kJ / m 2 , 45 kJ / m 2 and ranges formed by any two of the above values and values within the ranges). The unnotched Charpy impact strength is determined according to the method in GB / T 1043-2008.

[0027] According to the present application, preferably, the weight average molecular weight of the modified polystyrene is 100-400 kg / mol (for example, it can be 100 kg / mol, 150 kg / mol, 200 kg / mol, 220 kg / mol, 250 kg / mol, 280 kg / mol, 300 kg / mol, 320 kg / mol, 350 kg / mol, 380 kg / mol, 400 kg / mol and ranges formed by any two of the above values and values within the ranges).

[0028] According to the present application, preferably, the weight average molecular weight of the polyconjugated diene-styrene graft structure is 150-200 kg / mol (for example, it can be 160-180 kg / mol) and the molecular weight distribution is 2-3. When the ranges as described above are met, the impact strength and the melt strength can be further ensured.

[0029] According to the present application, the polyconjugated diene can be polybutadiene, in particular 1,4-polybutadiene, for which it is preferred that the polyconjugated diene-styrene graft structure has the structure as shown in (I):

[0030]

[0031] Preferably, in formula (I), the amount of m and n is such that the mass ratio of the structural units from butadiene to the structural units from styrene is 1:0.4-0.95.

[0032] According to the present application, preferably, in the polyconjugated diene-styrene graft structure, the polyconjugated diene part is provided by low cis 1,4-polybutadiene and the content of cis 1,4-polybutadiene structure in the low cis 1,4-polybutadiene is not higher than 40 wt%, more preferably 32-38 wt%.

[0033] According to the present application, preferably, the polyconjugated diene-styrene graft structure is distributed in the modified polystyrene in the form of particles, which particle size can be, for example, 100-800 nm, more preferably 150-600 nm, and most preferably 200-500 nm. The content of the polyconjugated diene-styrene graft structure in the modified polystyrene is small, and the particle size is also small, which can further improve the compatibility of the material with the thermoplastic resin and the rubber phase while keeping the properties of the modified polystyrene unaffected, and the obtained polymer particles maintain a suitable melt strength, which is convenient for the preparation of free foams.

[0034] According to the present application, in the case where the polyconjugated diene-styrene graft structure is distributed in the modified polystyrene in the form of particles, the remaining polystyrene component can be considered as linear polystyrene formed by self-polymerization, and the molecular weight thereof can be adjusted within a wide range, for example, the weight average molecular weight thereof can be 200-380 kg / mol (for example, 250 kg / mol, 280 kg / mol, 300 kg / mol, 320 kg / mol, 350 kg / mol, and any two of the above values and the values within the range formed by the two values).

[0035] According to the present application, although the polyconjugated diene part in the polyconjugated diene-styrene graft structure can be provided by a linear low-cis rubber, can also be provided by a low-cis star-shaped rubber, or a combination of both, the inventors of the present application have found that, when a low-cis star-shaped rubber is introduced as the polyconjugated diene part, the particles of the polyconjugated diene-styrene graft structure in the obtained modified polystyrene have a higher roundness, the thermoplastic resin and the rubber component in the formed polystyrene composition can be better dispersed and compatible with the modified polystyrene, a polystyrene material with higher melt strength is formed, and a polystyrene free foam with superior performance is obtained by foaming. Preferably, the polyconjugated diene part is a low-cis star-shaped rubber, and when the low-cis star-shaped rubber is present in a styrene solution at a concentration of 5% by weight at 25°C, the viscosity of the solution is 15-70 mPa·s, more preferably 20-50 mPa·s, and most preferably 25-40 mPa·s. Among them, the viscosity of the solution obtained when the linear low-cis rubber is present in a styrene solution at a concentration of 5% by weight at 25°C can be, for example, greater than 70 mPa·s, for example, can reach 100-200 mPa·s.

[0036] According to the present application, the modified polystyrene described above can be prepared according to the requirements of the modified polystyrene of the present application, for example, the preparation method thereof comprises: mixing styrene and polyconjugated diene to perform a polymerization reaction. It can be understood that, in the polymerization reaction process, the polymerization of styrene and the grafting reaction of styrene on the polyconjugated diene are included, and a polystyrene and polyconjugated diene graft copolymer chain segment structure can be obtained. The amount of the polyconjugated diene can be appropriately adjusted according to the content of the polyconjugated diene-styrene graft structure in the modified polystyrene required, for example, it can be 50 ppm or more, preferably 50-15000 ppm, for example, 80-11000 ppm (for example, it can be 100 ppm, 200 ppm, 300 ppm, 400 ppm, 500 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm, 1000 ppm, 1100 ppm, 1200 ppm, 1300 ppm, 1400 ppm, 1500 ppm, 1600 ppm, 1700 ppm, 1800 ppm, 2000 ppm, 3000 ppm, 4000 ppm, 5000 ppm and any two numerical values formed range and values within the range), preferably 300-800 ppm, more preferably 490-700 ppm.

[0037] According to the present application, the polymerization reaction can be performed in a non-reactive atmosphere, such as a nitrogen-containing atmosphere.

[0038] According to the present application, the polymerization reaction can be a bulk polymerization reaction performed in the presence of an initiator selected from at least one of a monofunctional initiator, a difunctional initiator and a tetrafunctional initiator. The monofunctional initiator can be selected from at least one of potassium persulfate, dicumyl peroxide, cumene hydroperoxide and benzoyl peroxide, for example. The difunctional initiator can be selected from dicumyl peroxide and / or tert-butyl peroxy-2-ethylhexyl carbonate, for example. The tetrafunctional initiator can be selected from polyether polytert-butyl peroxycarbonate and / or 2,2'-(4,4'-di(tert-butylperoxy)cyclohexyl)propane, for example.

[0039] According to the present application, the weight amount of the initiator is 300-1500 ppm (for example, 300 ppm, 400 ppm, 500 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm, 1000 ppm, 1100 ppm, 1200 ppm, 1300 ppm, 1400 ppm, 1500 ppm and any two numerical values formed range and values within the range) of the weight amount of styrene, preferably 500-1200 ppm, most preferably 800-1000 ppm.

[0040] According to the present application, the material of the polymerization reaction can further introduce conventional selected auxiliary agents, such as at least one of anti-aging agents, preferably antioxidants and heat stabilizers. The antioxidant is preferably selected from at least one of β-(3,5 di-tert-butyl-4-hydroxyphenyl) propyl octadecyl ester (antioxidant 1076), 2,2,4-trimethyl-1,2-dihydroquinoline polymer (antioxidant RD), tetra[3-(3,5-di-tert-butyl-4-hydroxy) phenyl propionic acid] pentaerythritol ester (antioxidant 1010), tris(2,4-di-tert-butyl) phenyl phosphite (antioxidant 168), dioctadecyl pentaerythritol bisphosphite (antioxidant 618), N-cyclohexyl-N'-phenyl-p-phenylenediamine (antioxidant 4010) and 2,2'-methylenebis(4-methyl-6-tert-butyl) phenol (antioxidant 2246), and the heat stabilizer is preferably selected from at least one of zinc stearate, lead stearate and cadmium stearate. The above anti-aging agents can be added after the polyconjugated diene and styrene are mixed uniformly and the polyconjugated diene is dissolved. The amount of the anti-aging agent is not particularly limited and can be a conventional selection in the art, for example, the weight amount of the anti-aging agent can be 1-50 ppm of the weight amount of styrene.

[0041] According to the present application, preferably, the conditions of the polymerization reaction include: first reacting at 100-108°C for 3.5-5h, then reacting at 110-120°C for 0.8-1.2h, again reacting at 125-138°C for 0.8-1.2h, and finally reacting at 140-150°C for 0.3-1h. By using the above segmented polymerization method, the conversion rate and reaction rate can be improved, and the molecular weight can be better controlled in a suitable range, so that the obtained modified polystyrene can better improve the compatibility with the thermoplastic resin and the rubber component, and improve the foaming performance of the obtained polystyrene.

[0042] It can be understood that in the polymerization reaction, styrene can be used as a reactant or a solvent, and no other solvent can be additionally used. Preferably, the polymerization reaction is carried out in the presence of a solvent selected from aromatic hydrocarbon solvents, more preferably at least one of toluene, xylene and ethylbenzene. The amount of the solvent is not particularly limited and can be a conventional selection in the art, preferably the amount of the solvent is 0-40 wt% of the amount of styrene, more preferably 10-20 wt%.

[0043] According to the present application, the polyconjugated diene is selected as described above, and can be polybutadiene, in particular 1,4-polybutadiene, preferably low cis 1,4-polybutadiene. The content of cis 1,4-polybutadiene structure in the low cis 1,4-polybutadiene is not higher than 40% by weight, more preferably 32-38% by weight. The polyconjugated diene can be linear low cis rubber, or low cis star-shaped rubber, or a combination of both, and the low cis 1,4-polybutadiene is preferably low cis star-shaped rubber, which has a viscosity of 15-70 mPa·s, more preferably 20-50 mPa·s, and most preferably 25-40 mPa·s in a styrene solution at 25°C, with a concentration of 5% by weight.

[0044] According to a particularly preferred embodiment of the present application, the styrene, 1,4-polybutadiene and solvent are first mixed, and stirred to dissolve the 1,4-polybutadiene, and then the anti-aging agent is added. Then, the air in the reaction vessel is replaced with a non-reactive gas such as nitrogen, the initiator is added, and then the stirring is started, and the temperature is raised, and the polymerization is carried out according to the method of the above-described staged polymerization to obtain the product.

[0045] According to the present application, preferably, the method further comprises: after the polymerization reaction is completed, removing the unreacted monomers and excess solvent from the viscous body obtained by polymerization. The method for removing the monomers and solvent can be a conventional selection in the art, for example, flash evaporation can be carried out under vacuum at 200-220°C, and the above method can be carried out in a devolatilizer. More preferably, after the monomers and solvent are removed, cooling and granulation are carried out to obtain the modified polystyrene. Using the above-described method, the unreacted monomers and solvent can be removed as much as possible.

[0046] According to the present application, in order to enable the rubber to play a better reinforcing role in the system formed by the thermoplastic resin and the modified polystyrene, preferably, the content of the rubber is 5-200 parts by weight (10 parts by weight, 15 parts by weight, 20 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight, 100 parts by weight, 120 parts by weight, 140 parts by weight, 150 parts by weight, 170 parts by weight, 200 parts by weight, etc., as well as ranges formed by any two of the above values and values within the ranges), preferably 30-150 parts by weight, and more preferably 40-100 parts by weight, relative to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene.

[0047] According to the present application, in order to be able to produce the desired free foams, it is necessary in the present application to make the weight ratio of the content of the modified polystyrene and the thermoplastic resin be 1 or less, wherein the amount of the thermoplastic resin can be relatively large, in order to improve the better cooperation of the modified polystyrene and the thermoplastic resin, preferably, the weight ratio of the content of the modified polystyrene and the thermoplastic resin can be 5-90: 100 (8: 100, 10: 100, 15: 100, 20: 100, 22: 100, 25: 100, 30: 100, 35: 100, 40: 100, 50: 100, 60: 100, 70: 100, 80: 100, etc. and the range formed by any two of the above values and the values within the range), preferably 12-50: 100, more preferably 17-40: 100.

[0048] According to the present application, the thermoplastic resin can be appropriately selected from a variety of thermoplastic resins, for example, can be one or more of polyolefin resins, SBR resins, ABS resins, polyamide resins, etc. As the polyolefin resin, one or more of polyethylene, other ethylene copolymers, other substituted ethylene polymers, polypropylene, polybutylene, polyamylene, etc. can be listed, for example, the other ethylene copolymers can be EVA resins, for example, the other substituted ethylene polymers can be one or more of PVC resins, high-chlorinated polyethylene resins (HCPE), etc. Preferably, polyethylene or polypropylene.

[0049] In a preferred embodiment of the present application, the thermoplastic resin is a polyolefin resin, in particular a polyethylene and / or polypropylene resin, for example, the polyolefin resin has a melt flow index of 0.5-20 g / 10 min, preferably 1-15 g / 10 min, more preferably 1.5-10 g / 10 min (determined by the 230°C, 2.16 kg load melt flow rate test method described in GB / T 3682-2000); a density of 0.85-0.94 g / cm 3 , preferably 0.88-0.93 g / cm 3 , more preferably 0.895-0.91 g / cm 3 ; a tensile strength of 15-40 MPa, preferably 20-35 MPa, more preferably 22-30 MPa; a flexural modulus of 400-2000 MPa, preferably 600-1800 MPa, more preferably 750-1500 MPa (for example, 850-1100 MPa).

[0050] According to the present application, the rubber can be selected from a variety of rubber materials, such as one or more of natural rubber, styrene-butadiene rubber, carboxylated styrene-butadiene rubber, nitrile rubber, carboxylated nitrile rubber, chloroprene rubber, polybutadiene, acrylate rubber, butadiene styrene pyrene rubber, isoprene rubber, butyl rubber, ethylene propylene rubber, polysulfide rubber, acrylate-butadiene rubber, polyurethane rubber, or fluororubber, especially the vulcanized products of the above-mentioned rubbers. Preferably, the rubber is a powdered rubber having an average particle size of 0.02 to 1 μm, preferably 0.05 to 0.5 μm, and more preferably 0.1 to 0.3 μm. More preferably, the rubber is a powdered rubber having a crosslinked structure, and the rubber particles of the powdered rubber preferably have a homogeneous structure. The gel content of the powdered rubber is preferably 60% by weight or more (such as 65% by weight, 70% by weight, 75% by weight, 80% by weight, 82% by weight, 85% by weight, 90% by weight, 92% by weight, 95% by weight, 98% by weight, and ranges formed by any two of the above values and values within the ranges), and more preferably 80% by weight or more, and even more preferably 90 to 95% by weight.

[0051] According to the present application, the powdered rubber having a crosslinked structure described above can be a commercially available product, or can be obtained by a conventional method in the art, such as by fixing the particle size of the rubber particles by irradiation crosslinking of a corresponding rubber latex, such as the fully vulcanized powdered rubber described in Chinese Patents CN00816450.9 and CN00130386.4.

[0052] According to the present application, the composition can also incorporate conventional additives for polystyrene, such as an age resistor, particularly as described above, in an amount that can be adjusted within a wide range, such as 0.001 to 1.5 parts by weight, preferably 0.01 to 0.5 parts by weight, of the age resistor per 100 parts by weight of the polystyrene composition; a colorant (such as graphite powder), in an amount that can be adjusted within a wide range, such as 1 to 8 parts by weight, preferably 2 to 5 parts by weight, of the colorant per 100 parts by weight of the polystyrene composition; an antistatic agent, in an amount that can be adjusted within a wide range, such as 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, of the antistatic agent per 100 parts by weight of the polystyrene composition; a lubricant, in an amount that can be adjusted within a wide range, such as 0.1 to 10 parts by weight, preferably 0.5 to 3 parts by weight, of the lubricant per 100 parts by weight of the polystyrene composition; and an anti-aging agent, in an amount that can be adjusted within a wide range, such as 0.01 to 5 parts by weight, preferably 0.1 to 2 parts by weight, of the anti-aging agent per 100 parts by weight of the polystyrene composition.

[0053] The second aspect of the present application provides a foamable polystyrene particle suitable for free foams, the polystyrene particle comprising a rubber phase, a thermoplastic resin phase and a modified polystyrene phase, the weight ratio of the content of the modified polystyrene phase and the thermoplastic resin phase is 1 or less; and the content of the rubber phase is less than 250 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin phase and the modified polystyrene phase; the modified polystyrene comprises a polyconjugated diene-styrene graft structure, and the melt strength of the polystyrene particle at 210°C is 0.1 N or more.

[0054] According to the present application, the polystyrene particle can be considered as a polymer material particle formed by the rubber, the thermoplastic resin and the modified polystyrene, the rubber phase is formed by the rubber as described above, the thermoplastic resin phase is formed by the thermoplastic resin as described above, and the modified polystyrene phase is formed by the modified polystyrene as described above, and the polymer material particle can be considered as a blend of the rubber, the thermoplastic resin and the modified polystyrene.

[0055] In the process of polymer foaming, the formation of polymer cells is actually the stretching process of cell walls, and if there is not enough melt strength, the cell walls cannot withstand the stretching stress, which will cause the cell to rupture and cannot be formed. The polystyrene particle formed by the rubber, the thermoplastic resin and the modified polystyrene according to the present application has excellent foamability, and the melt strength of the polystyrene particle at 210°C can reach 0.12 N or more, preferably 0.15 N or more, for example, 0.16-0.2 N.

[0056] According to the present application, it can be considered that the content of the rubber, the thermoplastic resin and the modified polystyrene in the above-mentioned polystyrene composition corresponds to the content of the rubber phase, the thermoplastic resin phase and the modified polystyrene phase in the polystyrene particles provided by the present application, that is, preferably, the content of the rubber phase is 5-200 parts by weight (10 parts by weight, 15 parts by weight, 20 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight, 100 parts by weight, 120 parts by weight, 140 parts by weight, 150 parts by weight, 170 parts by weight, 200 parts by weight, etc. and ranges formed by any two of the above values and values within the ranges) relative to 1000 parts by weight of the total weight of the thermoplastic resin phase and the modified polystyrene phase, preferably 30-150 parts by weight, more preferably 40-100 parts by weight. Preferably, the weight ratio of the content of the modified polystyrene phase and the thermoplastic resin phase is 5-90:100 (8:100, 10:100, 15:100, 20:100, 22:100, 25:100, 30:100, 35:100, 40:100, 50:100, 60:100, 70:100, 80:100, etc. and ranges formed by any two of the above values and values within the ranges), preferably 12-50:100, more preferably 17-40:100.

[0057] According to the present application, the particle size of the polystyrene particles can vary within a wide range, for example, it can be 0.01-5 mm, which can be selected as needed, for example, 0.5-3 mm, 0.1-2 mm, 0.5-1 mm, etc.

[0058] The present application provides a method for preparing the foamable polystyrene particles suitable for free foams, which comprises blending the above-mentioned polystyrene composition.

[0059] In the present application, the blending can be carried out by the methods commonly used in the art for preparing polymer blends, and the mechanical blending method is usually used, for example, the blending is carried out at a temperature above the softening point (or melting point) of the polymer by using an open mill, an internal mixer or a screw extruder, etc. The present application does not have a particular limitation in this regard, for example, a twin-screw extruder can be used to carry out extrusion granulation at a temperature above 180°C (190°C, 200°C, 220°C, 250°C or 260°C, etc.), and the mixing treatment can be carried out in a blender before the extrusion granulation, which is also not particularly limited in the present application.

[0060] The fourth aspect of the present application provides a polystyrene foam composition suitable for free foams, which contains the foamable polystyrene particles obtained by the above-mentioned method or the method provided in the third aspect.

[0061] According to the present application, the polystyrene particles in the polystyrene foam composition are as described above, which will not be repeated here.

[0062] In addition to containing the above-mentioned polystyrene particles, the polystyrene foam composition can also contain dispersing media and auxiliary components commonly used in the art, wherein the dispersing media can be, for example, an aqueous medium, which can be water or an aqueous solution formed by other solvents, such as a mixed solvent of a lower alcohol such as methanol or ethanol and water. The amount of the dispersing medium can be adjusted within a wide range, for example, the amount of the dispersing medium can be 100-800 parts by weight, preferably 150-500 parts by weight, for example 200-400 parts by weight, relative to 100 parts by weight of the foamable polystyrene particles.

[0063] The auxiliary components can be adjusted as needed, for example, can be selected from one or more of surfactants, dispersants, dispersion enhancers, etc. Among them, the surfactant can be, for example, one or more of sodium dodecyl benzene sulfonate, sodium alpha-olefin sulfonate, triethanolamine laurate, sorbitan monolaurate, etc.; the amount of surfactant can be, for example, 0.01-1 parts by weight (for example, 0.05-0.8 parts by weight, 0.1-0.5 parts by weight) relative to 1000 parts by weight of the foamable polystyrene particles. The dispersant can be, for example, one or more of kaolinite, montmorillonite, hectorite, boehmite, palygorskite, sepiolite, illite, chlorite and vermiculite, etc.; the amount of dispersant can be, for example, 0.1-6 parts by weight (for example, 0.5-5 parts by weight, 1-3 parts by weight) relative to 1000 parts by weight of the foamable polystyrene particles. The dispersion enhancer can be, for example, at least one of polyaluminum chloride PAC, aluminum sulfate, alum, ferric trichloride, polymeric ferric sulfate, aluminum chloride, magnesium aluminum silicate, lime, polyacrylamide, PEO, sodium polyacrylate, chitosan, cationic melamine polymer, tannin, cationic starch, cationic dicyandiamide polymer, polyamine, polydimethyl diallyl ammonium chloride, etc.; the amount of dispersion enhancer can be, for example, 0.01-1 parts by weight (for example, 0.05-0.8 parts by weight, 0.1-0.5 parts by weight) relative to 1000 parts by weight of the foamable polystyrene particles. In at least one preferred embodiment of the present application, the auxiliary components are selected from surfactants, dispersants and dispersion enhancers.

[0064] The fifth aspect of the present application provides a method for preparing a polystyrene free foamed body, which comprises: providing the above-mentioned polystyrene foamable body composition, the above-mentioned polystyrene particles or the polystyrene particles prepared by the above-mentioned method, and subjecting the same to free foaming treatment.

[0065] According to the present application, the free foaming treatment can be carried out in various ways of free foaming. For example, the free foaming treatment can be carried out in the following way: the above-mentioned polystyrene foamable body composition or the above-mentioned polystyrene particles is mixed with a foaming agent (which can be in various contact modes as long as the polystyrene particles are contacted with the foaming agent and the foaming agent is dispersed among the polystyrene particles), and a foamed bead is prepared (for example, by extrusion, molding or autoclaving), and then a foamed body is prepared by molding. Alternatively, the free foaming treatment can be carried out in the following way: the above-mentioned polystyrene foamable body composition or the above-mentioned polystyrene particles is extruded and foamed in a screw extruder. Alternatively, the free foaming treatment can be carried out in the following way: the above-mentioned polystyrene foamable body composition or the above-mentioned polystyrene particles is first extruded to prepare a plate, and then the plate is sealed in a molding machine, and then the plate is foamed by opening the mold. In the above-mentioned ways, the foaming agent can be introduced during the preparation of the plate by extrusion or during the sealing of the plate in the molding machine. The specific foaming and molding process conditions in the above-mentioned ways can be selected according to the prior art, and thus will not be described herein.

[0066] According to the present application, both physical foaming and chemical foaming can be used. The specific process is known to those skilled in the art, and thus will not be described herein.

[0067] According to the present application, the foaming agent used can be a chemical foaming agent or a physical foaming agent. The chemical foaming agent includes, but is not limited to, at least one of azodicarbonamide (AC foaming agent), p-toluenesulfonyl hydrazide, aminourea, tetrazole, sodium bicarbonate and sodium citrate. The physical foaming agent can be an organic physical foaming agent or an inorganic physical foaming agent. The organic physical foaming agent includes, but is not limited to, at least one of aliphatic hydrocarbons such as propane, butane, pentane, hexane and heptane, alicyclic hydrocarbons such as cyclobutane and cyclohexane, and halogenated hydrocarbons such as chlorofluoromethane, trifluoromethane, 1,2-difluoroethane, 1,2,2,2-tetrafluoroethane, methyl chloride, ethyl chloride and dichloromethane. The inorganic physical foaming agent includes, but is not limited to, at least one of air, nitrogen, carbon dioxide, oxygen and water.

[0068] The sixth aspect of the present application provides a polystyrene free foamed body prepared by the above-mentioned method. As described above, the polystyrene free foamed body of the present application is prepared by the above-mentioned free foaming method of the present application, and can have excellent foaming performance and physical properties.

[0069] The seventh aspect of the present application provides a polystyrene free foam, which contains the polystyrene composition described above or a polystyrene phase formed by the expandable polystyrene particles described above.

[0070] The polystyrene foam provided by the sixth aspect of the present application, although can be considered to be directly prepared by the method of the fifth aspect of the present application, can satisfy the following description for polystyrene foam as the polystyrene foam provided by the seventh aspect of the present application.

[0071] According to the present application, the polystyrene free foam has excellent physical properties and relatively low thermal conductivity, wherein the polystyrene foam has relatively high compressive strength and tensile strength, for example, the compressive strength of the polystyrene foam obtained by the present application is 0.5 MPa or more (for example, 0.55 MPa, 0.58 MPa, 0.6 MPa, 0.7 MPa, 0.75 MPa, 0.8 MPa or more, and any two of the above values and the values within the range form a range), preferably 0.65 MPa or more, more preferably 0.75 MPa or more, for example, 0.75-0.95 MPa. The tensile strength of the polystyrene foam can be, for example, 0.8 MPa or more (for example, 0.85 MPa, 0.9 MPa, 1 MPa, 1.1 MPa, 1.15 MPa, 1.2 MPa, 1.25 MPa, 1.3 MPa, 1.35 MPa or more, and any two of the above values and the values within the range form a range), preferably 0.9 MPa or more, more preferably 1 MPa or more, for example, 1.16-1.4 MPa. The thermal conductivity of the polystyrene foam can be reduced to a low level, for example, the thermal conductivity can be 0.045 W·m -1 ·K -1 For example, 0.042 W·m -1 ·K -1 , 0.040 W·m -1 ·K -1 , 0.039 W·m -1 ·K -1 , 0.037 W·m -1 ·K -1 , 0.035 W·m -1 ·K -1 , 0.033 W·m -1 ·K -1 , 0.032 W·m -1 ·K -1 , 0.028 W·m -1 ·K -1 and any two of the above values and the values within the range form a range), preferably 0.04 W·m -1 ·K -1 , more preferably 0.038 W·m-1 ·K -1 The following, for example, is 0.030-0.036 W·m -1 ·K -1 .

[0072] The apparent density of the polystyrene foam can be adjusted within a wide range, for example, can be 200 g / L or less (for example, 150 g / L, 100 g / L, 90 g / L, 80 g / L, 70 g / L, 60 g / L, 55 g / L, 50 g / L, 45 g / L, 40 g / L, 35 g / L, 30 g / L, 20 g / L, 15 g / L, and any range formed by any two of the above values and values within the range), preferably 100 g / L or less, more preferably 15-90 g / L, for example, 40-52 g / L.

[0073] The polystyrene foam obtained by the present application has a thinner skin layer, a honeycomb-like cell, excellent mechanical properties, and good thermal insulation and shock absorption performance.

[0074] The present application will be described in detail below through examples.

[0075] In the following examples and comparative examples:

[0076] Low-cis star-shaped rubber 730AX, which is a 1,4-polybutadiene having a content of cis 1,4-polybutadiene structure of 33% by weight, was purchased from Asahi Kasei Corporation, and when present in a styrene solution at a concentration of 5% by weight at 25°C, the viscosity of the solution was 35 mPa·s.

[0077] Low-cis linear rubber A35AE, which is a 1,4-polybutadiene having a content of cis 1,4-polybutadiene structure of 35% by weight, was purchased from Takachiho Petrochemical Corporation, and when present in a styrene solution at a concentration of 5% by weight at 25°C, the viscosity of the solution was 130 mPa·s.

[0078] The gloss of the material at 60° was determined according to the method in GB / T 8807-1988.

[0079] The light transmittance of the material at a thickness of 2 mm was determined according to the method in GB / T 2410-2008.

[0080] The Charpy unnotched impact strength of the material was determined according to the method in GB / T 1043-2008.

[0081] The method for separating 1,4-polybutadiene-styrene graft copolymer from modified polystyrene is as follows: a certain amount of polymer sample is accurately weighed, placed in a conical flask with a stopper, 2-butanone reagent is added, and placed on a shaking bed for dissolution at room temperature. A stirring rod is placed in the conical flask, the conical flask is placed on a magnetic heating stirrer, and a spherical condenser is connected. The temperature of the magnetic heating stirrer is set to 200℃, and the sample is fully dissolved again. The dissolved polymer sample in the conical flask is evenly poured into two centrifuge cups, then the cup covers are tightly screwed, and the water stains or other impurities that may be adhered to the cup wall are wiped off, and then the two centrifuge cups are placed in the centrifuge in a symmetrical manner, and centrifuged at 14500 rpm for 1 hour. The rubber phase sample after centrifugation is adhered to the cup wall in a block, which is 1,4-polybutadiene-styrene graft copolymer. Then the liquid phase obtained by centrifugation is placed in methanol solvent to form a precipitate, and the precipitate is separated and dried.

[0082] The weight average molecular weight is measured by gel permeation chromatography (GPC), and the specific method is as follows: a PL-GPC 220 type high performance liquid chromatograph produced by Polymer Laboratories Company in the United Kingdom is used, three Plgel 10 μm MIXED-B columns are connected in series, tetrahydrofuran is used as the mobile phase for testing, and the testing temperature is 25℃.

[0083] The particle size is tested by using a Malvern particle size analyzer.

[0084] The properties of the modified polystyrene, polystyrene particles and foamed molding are tested according to the following methods:

[0085] (1) Melt strength of modified polystyrene and polystyrene particles: Rheotens 71.97 melt strength tester of GOTTFERT Company in Germany, testing temperature 210℃, die diameter 2mm, gap between stretching wheels 0.4mm, die distance from the center of stretching wheel 60mm, stretching acceleration 20mm / s 2 ;

[0086] (2) Compressive strength (50%) of foamed molding: determined according to the method specified in ISO 844.

[0087] (3) Tensile strength of foamed molding: determined according to the method specified in ISO 1798.

[0088] (4) Density of foamed molding: GB / T 6343-2009 Determination of apparent density of foamed plastics and rubbers.

[0089] (5) Thermal conductivity coefficient of foamed molding: determined according to the method specified in GB / T 10294-2008.

[0090] 1#Full-vulcanized SBR powder is "Narpow" super-fine full-vulcanized SBR powder produced by Beijing Chemical Research Institute, with the model number VP108.

[0091] 2#Full-vulcanized SBR powder is "Narpow" super-fine full-vulcanized SBR powder produced by Beijing Chemical Research Institute, with the model number VP121.

[0092] 1#Polypropylene is E02ES polypropylene product produced by Sinopec Zhenhai Refinery, with the melt flow index of 1.8 g / 10 min, the density of 0.901 g / cm 3 , the tensile strength of 27.5 MPa, and the bending modulus of 1050 MPa.

[0093] 2#Polypropylene is E680E polypropylene product produced by Sinopec Shanghai Petrochemical, with the melt flow index of 8.1 g / 10 min, the density of 0.898 g / cm 3 , the tensile strength of 24.4 MPa, and the bending modulus of 850 MPa.

[0094] 3#Polypropylene is WB140 polypropylene product produced by Borealis, with the melt flow index of 2.0 g / 10 min, the density of 0.904 g / cm 3 , the tensile strength of 28.1 MPa, and the bending modulus of 1500 MPa.

[0095] Example 1

[0096] (1) Preparation of modified polystyrene

[0097] 1 g of low-cis star-shaped rubber 730AX, 2000 g of styrene, and 200 g of ethylbenzene were added into a kettle, stirred uniformly, and dissolved for 10 hours until the rubber was dissolved as much as possible, and then 0.01 g of antioxidant 1076 was added. The air in the kettle was replaced with nitrogen. 2 g of initiator 2,2'-(4,4'-di(t-butylperoxy)cyclohexyl)propane was added. The stirring was started and the rotation speed was maintained at 200 rpm, and the temperature was raised, and the polymerization was carried out at 107℃ for 4 hours, at 116℃ for 1 hour, at 131℃ for 1 hour, and at 150℃ for 0.3 hours.

[0098] After the polymerization reaction was completed, the polymerized material was transferred to a devolatilizer, and flash evaporation was carried out at 210℃ and under vacuum to remove monomers and solvents. 1540 g of product was obtained, and the conversion rate of styrene was 77%. Then, cooling, granulation, and sample preparation were carried out to obtain a sample, and the test results are shown below.

[0099]

[0100] (2) Preparation of polystyrene particles

[0101] 650 g of 1# full vulcanized SBR powder rubber (gel content 90.4 wt%) with average particle size of about 0.1 μm, 2 kg of modified polystyrene obtained in step (1) and 8 kg of 1# polypropylene were mixed, 20 g of antioxidant 1010 was added, and after mixing by a high speed mixer, the mixture was extruded and pelletized by a ZSK-25 twin screw extruder, the temperature of the extruder head was 220°C. The melt strength of the obtained pellets was measured, and the test results are shown in Table 1.

[0102] (3) Preparation of free foamed body

[0103] The mold installed between the molding machines was heated to a foaming temperature of 160°C, the polystyrene pellets obtained in step (2) were prepared into a plate by extrusion, and were placed in the molding machine, the molding machine was closed, and the mold was sealed. Carbon dioxide gas was injected to diffuse into the elastomer plate, the pressure was 100 bar, and after saturation for 1 hour, the diffusion equilibrium was reached, and the free foaming was carried out by one-time pressure relief valve opening and mold opening, and the cooling and shaping were carried out, and the free foamed body was obtained. The apparent density, compression strength, tensile strength and thermal conductivity coefficient were measured, and the results are shown in Table 1.

[0104] Example 2

[0105] (1) Preparation of modified polystyrene

[0106] 1.2 g of low-cis star-shaped rubber 730AX, 2000 g of styrene and 300 g of toluene were added to the kettle, stirred uniformly, and dissolved for 11 hours until the rubber was dissolved as much as possible, and then 0.02 g of antioxidant 1076 was added. The air in the kettle was replaced with nitrogen. 1.6 g of initiator polyether polytert-butyl peroxide carbonate was added. The stirring was started and the rotation speed was maintained at 180 rpm, and the temperature was raised, and the polymerization was carried out at 100°C for 3.5 hours, at 110°C for 1.2 hours, at 138°C for 1.2 hours, and at 145°C for 0.8 hours.

[0107] After the polymerization reaction was completed, the polymerized material was transferred to a devolatilizer, and flash evaporation was carried out at 200°C and under vacuum to remove monomers and solvents. The product was obtained in an amount of 1578 g, and the conversion rate of styrene was 78.8%. Then, cooling, granulation and sample preparation were carried out, and the measurement results are shown as follows.

[0108]

[0109]

[0110] (2) Preparation of polystyrene elastomer pellets

[0111] The 450 g of 2# full vulcanized SBR powder rubber (gel content 94.5 wt%) having an average particle size of about 0.15 μm, 1.5 kg of the modified polystyrene obtained in step (1) and 8.5 kg of 2# polypropylene were mixed, and 15 g of antioxidant 1010 was added. After mixing by a high speed mixer, the mixture was extruded and pelletized by a ZSK-25 twin screw extruder, and the temperature of the extruder head was 200°C. The melt strength of the obtained pellets was measured, and the results are shown in Table 1.

[0112] (3) Preparation of free foamed body

[0113] In a reaction vessel, 1 kg of the polystyrene particles obtained in step (2) was mixed with a dispersing medium (deionized water) 3 kg, a surfactant (sodium dodecylbenzenesulfonate) 0.3 g, a dispersant (kaolin) 3 g and a dispersion enhancer (aluminum sulfate) 0.2 g at one time. The residual air in the reaction vessel was removed using carbon dioxide as a foaming agent, and the vessel was tightly capped after removing the air. The carbon dioxide was fed into the reaction vessel, and the pressure was initially adjusted until it was stable. Then, the temperature was increased to 140°C while stirring at a constant rate. Subsequently, the pressure in the vessel was adjusted to 6 MPa, which was the required pressure for foaming. The temperature was increased to 142°C at an average heating rate of 0.1°C / min. The stirring was continued for 0.5 hours under the foaming temperature and pressure. Then, the outlet of the reaction vessel was opened, and the material in the reaction vessel was discharged into a collection tank to obtain foamed beads.

[0114] The foamed beads obtained above were fed into a molding die in a molding machine, and molded for 15 minutes at a steam pressure of 2.0 bar. Then, the molded body was cured at a temperature of 100°C and a pressure of standard atmospheric pressure for 24 hours to obtain a free foamed body. The apparent density, compressive strength, tensile strength and thermal conductivity were measured, and the results are shown in Table 1.

[0115] Example 3

[0116] (1) Preparation of modified polystyrene

[0117] The modified polystyrene was prepared according to the same procedure of step (1) of Example 1.

[0118] (2) Preparation of polystyrene particles

[0119] The modified polystyrene obtained in step (1) was used in an amount of 2.5 kg, and 7.5 kg of 3# polypropylene was used instead of 1# polypropylene according to the same procedure of step (2) of Example 1.

[0120] (3) Preparation of free foamed body

[0121] In an extrusion foaming apparatus, 10 kg of the elastomer particles obtained in step (2) were introduced into a screw extruder, the foaming temperature was 160°C, the foaming pressure was 160 bar, supercritical carbon dioxide was added as a foaming agent, and melt mixing was performed in the screw at a screw rotation speed of 5 rpm and an extrusion amount of 45 kg / h. The melt in which the physical foaming agent was uniformly dispersed inside was extruded from an O-shaped die, the foaming agent escaped from the melt to form bubbles due to a rapid decrease in pressure, and a ring-shaped melt beam was observed to be foamed, the appearance was white and fine, and the cells were uniform. The ring-shaped melt beam was cooled, shaped, cut, pulled, and wound up at a pulling speed of 2.8 m / min. A free-foamed shaped body was obtained. The apparent density, compression strength, tensile strength, and thermal conductivity coefficient were measured, and the results are shown in Table 1.

[0122] Example 4

[0123] A polystyrene free-foamed shaped body was prepared according to the same method as in Example 1, except that in step (2), the amount of the full-vulcanized butadiene styrene powder rubber was 100 g.

[0124] The apparent density, compression strength, tensile strength, and thermal conductivity coefficient of the finally obtained polystyrene free-foamed shaped body were measured, and the results are shown in Table 1.

[0125] Example 5

[0126] A polystyrene free-foamed shaped body was prepared according to the same method as in Example 1, except that in step (2), the amount of the full-vulcanized butadiene styrene powder rubber was 1000 g.

[0127] The apparent density, compression strength, tensile strength, and thermal conductivity coefficient of the finally obtained polystyrene free-foamed shaped body were measured, and the results are shown in Table 1.

[0128] Example 6

[0129] A polystyrene free-foamed shaped body was prepared according to the same method as in Example 1, except that in step (1), the low-cis star-shaped rubber 730AX was replaced with a low-cis linear rubber A35AE, and the amount of the low-cis linear rubber A35AE added was 1 g, and the product 1485 g was obtained, the styrene conversion rate was 74.2%, and the rubber content was 673 ppm by weight.

[0130] The apparent density, compression strength, tensile strength, and thermal conductivity coefficient of the finally obtained polystyrene free-foamed shaped body were measured, and the results are shown in Table 1.

[0131] Example 7

[0132] The same procedure as in Example 1 was repeated, except that in step (1), 0.1 g of low-cis star-shaped rubber 730AX was used, and the weight content of 1,4-polybutadiene-styrene graft copolymer in the modified polystyrene thus obtained was 120 ppm. The same steps (2) and (3) as in Example 1 were repeated to produce a polystyrene structural foam.

[0133] The apparent density, compressive strength, tensile strength and thermal conductivity of the polystyrene structural foam thus obtained were measured, and the results are shown in Table 1.

[0134] Example 8

[0135] The same procedure as in Example 1 was repeated, except that in step (1), 4 g of low-cis star-shaped rubber 730AX was used, and the weight content of 1,4-polybutadiene-styrene graft copolymer in the modified polystyrene thus obtained was 5260 ppm. The same steps (2) and (3) as in Example 1 were repeated to produce a polystyrene structural foam.

[0136] The apparent density, compressive strength, tensile strength and thermal conductivity of the polystyrene structural foam thus obtained were measured, and the results are shown in Table 1.

[0137] Example 9

[0138] The same procedure as in Example 1 was repeated, except that in step (2), 2.8 kg of modified polystyrene and 7.2 kg of 1# polypropylene were used. The same steps (2) and (3) as in Example 1 were repeated to produce a polystyrene structural foam.

[0139] The apparent density, compressive strength, tensile strength and thermal conductivity of the polystyrene structural foam thus obtained were measured, and the results are shown in Table 1.

[0140] Example 10

[0141] The same procedure as in Example 1 was repeated, except that in step (2), 5 kg of modified polystyrene and 5 kg of 1# polypropylene were used. The same steps (2) and (3) as in Example 1 were repeated to produce a polystyrene structural foam.

[0142] The apparent density, compressive strength, tensile strength and thermal conductivity of the polystyrene structural foam thus obtained were measured, and the results are shown in Table 1.

[0143] Example 11

[0144] A polystyrene free-foam molded body was prepared according to the same procedure as in Example 1, except that 1.4 kg of the modified polystyrene and 8.6 kg of the polypropylene #1 were used in step (2). The polystyrene free-foam molded body was prepared according to the same procedure as in Example 1, except that 1.4 kg of the modified polystyrene and 8.6 kg of the polypropylene #1 were used in step (2).

[0145] The apparent density, compressive strength, tensile strength and thermal conductivity of the polystyrene free-foam molded body thus obtained were measured, and the results are shown in Table 1.

[0146] Example 12

[0147] A polystyrene free-foam molded body was prepared according to the same procedure as in Example 1, except that 1.4 kg of the modified polystyrene and 8.6 kg of the polypropylene #1 were used in step (2). The polystyrene free-foam molded body was prepared according to the same procedure as in Example 1, except that 1.4 kg of the modified polystyrene and 8.6 kg of the polypropylene #1 were used in step (2).

[0148] The apparent density, compressive strength, tensile strength and thermal conductivity of the polystyrene free-foam molded body thus obtained were measured, and the results are shown in Table 1.

[0149] Comparative Example 1

[0150] A polystyrene free-foam molded body was prepared according to the same procedure as in Example 1, except that 1.4 kg of the modified polystyrene and 8.6 kg of the polypropylene #1 were used in step (2). The polystyrene free-foam molded body was prepared according to the same procedure as in Example 1, except that 1.4 kg of the modified polystyrene and 8.6 kg of the polypropylene #1 were used in step (2).

[0151] The apparent density, compressive strength, tensile strength and thermal conductivity of the polystyrene free-foam molded body thus obtained were measured, and the results are shown in Table 1.

[0152] Comparative Example 2

[0153] A polystyrene free-foam molded body was prepared according to the same procedure as in Example 1, except that 1.4 kg of the modified polystyrene and 8.6 kg of the polypropylene #1 were used in step (2). The polystyrene free-foam molded body was prepared according to the same procedure as in Example 1, except that 1.4 kg of the modified polystyrene and 8.6 kg of the polypropylene #1 were used in step (2).

[0154] The apparent density, compressive strength, tensile strength and thermal conductivity of the polystyrene free-foam molded body thus obtained were measured, and the results are shown in Table 1.

[0155] Comparative Example 3

[0156] A polystyrene free-foam molded body was prepared according to the same procedure as in Example 1, except that 1.4 kg of the modified polystyrene and 8.6 kg of the polypropylene #1 were used in step (2). The polystyrene free-foam molded body was prepared according to the same procedure as in Example 1, except that 1.4 kg of the modified polystyrene and 8.6 kg of the polypropylene #1 were used in step (2).

[0157] The apparent density, compressive strength, tensile strength and thermal conductivity of the polystyrene free-foam molded body thus obtained were measured, and the results are shown in Table 1.

[0158] Comparative Example 4

[0159] The same method as in Example 1 was followed, except that no full-vulcanized SBR powder rubber was added in step (2).

[0160] The apparent density, compressive strength, tensile strength and thermal conductivity coefficient of the finally prepared free-foaming molded body were measured, and the results are shown in Table 1.

[0161] Comparative Example 5

[0162] The same method as in Example 1 was followed, except that step (1) was not performed, and instead the same amount of polystyrene 666D produced by Yanshan Petrochemical was directly used in step (2) to replace the modified polystyrene obtained in step (1) of Example 1.

[0163] The apparent density, compressive strength, tensile strength and thermal conductivity coefficient of the finally prepared free-foaming molded body were measured, and the results are shown in Table 1.

[0164] Comparative Example 6

[0165] (1) Preparation of polystyrene

[0166] 2000 g of styrene, 200 g of ethylbenzene and 0.01 g of antioxidant 1076 were added to a kettle, stirred uniformly, and the air in the kettle was replaced with nitrogen. 2 g of initiator 2,2'-(4,4'-di(t-butylperoxy)cyclohexyl)propane was added. The stirring was started and the stirring speed was maintained at 200 rpm, and the temperature was raised, and the polymerization was carried out at 107°C for 4 hours, at 116°C for 1 hour, at 131°C for 1 hour, and at 150°C for 0.3 hours.

[0167] The stirring speed was maintained at 200 rpm during the polymerization process, and after the completion of the polymerization process, the viscous body obtained by polymerization was discharged into a devolatilizer at 210°C and rapidly flashed under vacuum to remove unreacted monomers and solvent ethylbenzene. After cooling, granulation and sample preparation, polystyrene was obtained.

[0168] The polystyrene particles were prepared according to the process of step (2) of Example 1. The reaction was carried out according to the process of step (3) of Example 1 to obtain a foaming body.

[0169] Comparative Example 7

[0170] The polystyrene free-foaming molded body was prepared according to the same method as in Example 1, except that in step (2), the amount of full-vulcanized SBR powder rubber was 2 kg, and the total amount of modified polystyrene obtained in step (1) and 1# polypropylene was 8 kg (the weight ratio of modified polystyrene to 1# polypropylene was 1:4).

[0171] The polystyrene free-foaming molded body obtained was unevenly foamed and uneven, and the properties could not be tested.

[0172] Table 1

[0173]

[0174]

[0175] The preferred embodiments of the present application have been described in detail, but the present application is not limited thereto. Various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A polystyrene composition suitable for free foaming, characterized in that, The composition contains rubber, thermoplastic resin and modified polystyrene, wherein the weight ratio of the contents of the modified polystyrene and the thermoplastic resin is 1 or less; and the content of the rubber is less than 250 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene; and the modified polystyrene comprises poly-conjugated diene-styrene graft structure. The content of the poly-conjugated diene-styrene graft structure in the modified polystyrene is 100 ppm or more.

2. The composition of claim 1, wherein, The content of the rubber is 5 to 200 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene.

3. The composition of claim 2, wherein, The content of the rubber is 30 to 150 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene.

4. The composition of claim 3, wherein, The content of the rubber is 40 to 100 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin and the modified polystyrene.

5. The composition according to any one of claims 1-4, wherein, The weight ratio of the contents of the modified polystyrene and the thermoplastic resin is 5 to 90:

100.

6. The composition of claim 5, wherein, The weight ratio of the contents of the modified polystyrene and the thermoplastic resin is 12 to 50:

100.

7. The composition of claim 6, wherein, The weight ratio of the contents of the modified polystyrene and the thermoplastic resin is 17 to 40:

100.

8. The composition according to any one of claims 1-4, wherein, The rubber is a powder rubber, and the average particle diameter of the rubber is 0.02 to 1 μm.

9. The composition of claim 8, wherein, The average particle diameter of the rubber is 0.05 to 0.5 μm.

10. The composition of claim 9, wherein, The average particle diameter of the rubber is 0.1 to 0.3 μm.

11. The composition of any of claims 1-4, 6-7, and 9-10, wherein, The content of the poly-conjugated diene-styrene graft structure in the modified polystyrene is 100 to 12000 ppm.

12. The composition of claim 11, wherein, The content of the poly-conjugated diene-styrene graft structure in the modified polystyrene is 120 to 6000 ppm.

13. The composition of claim 12, wherein, The content of the poly-conjugated diene-styrene graft structure in the modified polystyrene is 700 to 1800 ppm.

14. The composition of claim 13, wherein, The content of the poly-conjugated diene-styrene graft structure in the modified polystyrene is 1100 to 1600 ppm.

15. The composition according to any one of claims 1 to 4, 6 to 7, 9 to 10 and 12 to 14, wherein the melt strength of the modified polystyrene at 210°C is 0.18 to 0.8 N; and / or, the gloss of the modified polystyrene at 60° is 80 to 100%; and / or, the light transmittance of the modified polystyrene at a thickness of 2 mm is 60 to 94%; and / or the Charpy notched impact strength of the modified polystyrene is 20-45 kJ / m 2 ; and / or, the weight average molecular weight of the modified polystyrene is 100 to 400 thousands g / mol; and / or, the weight average molecular weight of the poly-conjugated diene-styrene graft structure is 150 to 200 thousands g / mol, and the molecular weight distribution is 2 to 3; and / or, the poly-conjugated diene-styrene graft structure has the structure as shown in (I): （I）。 16. The composition of claim 15, wherein, In formula (I), the amounts of m and n are such that the mass of the structural unit from butadiene and the mass of the structural unit from styrene are in the ratio of 1:0.4 to 0.

95.

17. The composition of any of claims 1-4, 6-7, 9-10, 12-14, and 16, wherein, In the poly-conjugated diene-styrene graft structure, the poly-conjugated diene part is provided by low cis-1,4-polybutadiene, and the content of cis-1,4-polybutadiene structure in the low cis-1,4-polybutadiene is not higher than 40% by weight.

18. The composition of claim 17, wherein, The polyconjugated diene moiety is a low-cis star-shaped rubber, which, when present in a styrene solution at a concentration of 5% by weight at 25°C, has a viscosity of 15 to 70 mPa-s.

19. The composition of claim 18, wherein, The low-cis star-shaped rubber, when present in a styrene solution at a concentration of 5% by weight at 25°C, has a viscosity of 20 to 50 mPa-s.

20. The composition of claim 19, wherein, The low-cis star-shaped rubber, when present in a styrene solution at a concentration of 5% by weight at 25°C, has a viscosity of 25 to 40 mPa-s.

21. The composition of any of claims 1-4, 6-7, 9-10, 12-14, 16, and 18-20, wherein, The polyconjugated diene-styrene graft structure is distributed in the modified polystyrene in the form of particles having a particle size of 100 to 800 nm.

22. The composition of claim 21, wherein, The polyconjugated diene-styrene graft structure is distributed in the modified polystyrene in the form of particles having a particle size of 150 to 600 nm.

23. The composition of claim 22, wherein, The polyconjugated diene-styrene graft structure is distributed in the modified polystyrene in the form of particles having a particle size of 200 to 500 nm.

24. Expandable polystyrene particles suitable for use in free rise foam, characterised in that, The polystyrene particles contain a rubber phase, a thermoplastic resin phase, and a modified polystyrene phase, the weight ratio of the contents of the modified polystyrene phase and the thermoplastic resin phase is 1 or less; and the content of the rubber phase is less than 250 parts by weight with respect to 1000 parts by weight of the total weight of the thermoplastic resin phase and the modified polystyrene phase; the modified polystyrene includes a polyconjugated diene-styrene graft structure, and the polystyrene particles have a melt strength of 0.1 N or more at 210°C.

25. The expandable polystyrene particles according to claim 24, wherein, The polystyrene particles have a melt strength of 0.12 N or more at 210°C.

26. The expandable polystyrene particles according to claim 25, wherein, The polystyrene particles have a melt strength of 0.15 N or more at 210°C.

27. The expandable polystyrene particles according to any one of claims 24-26, wherein, The polystyrene particles have a tensile breaking strength of 16 MPa or more.

28. The expandable polystyrene particles according to claim 27, wherein, The polystyrene particles have a tensile breaking strength of 25 MPa or more.

29. The expandable polystyrene particles according to claim 28, wherein, The polystyrene particles have a tensile breaking strength of 30 to 45 MPa.

30. A process for the preparation of expandable polystyrene particles suitable for use in free rise foam, the process comprising: The composition according to any one of claims 1 to 23 is subjected to blending.

31. A polystyrene foam composition suitable for a free foam, which contains the foamable polystyrene particles according to any one of claims 24 to 29 or the foamable polystyrene particles obtained by the production method according to claim 30.

32. A method of making a polystyrene free foam, the method comprising: The polystyrene foam composition according to claim 31 or the foamable polystyrene particles according to any one of claims 24 to 29 or the foamable polystyrene particles obtained by the production method according to claim 30 are provided and subjected to a free foaming treatment.

33. A polystyrene free foam obtained by the production method of the polystyrene foam according to claim 32.

34. A polystyrene free foam characterized by, The polystyrene free foam contains a polystyrene phase formed of the polystyrene composition according to any one of claims 1 to 23 or the foamable polystyrene particles according to any one of claims 24 to 29.

35. The polystyrene free foam of claim 33 or 34, wherein, The polystyrene free foam has an apparent density of 200 g / L or less; and / or, the polystyrene free foam has a compressive strength of 0.5 MPa or more; and / or, the polystyrene free foam has a tensile strength of 0.8 MPa or more; and / or the polystyrene free foam has a thermal conductivity of 0.045 W-m -1 • K -1 The following.

36. The polystyrene free foam of claim 35, wherein, The apparent density of the polystyrene free foam is 100 g / L or less; and / or the compressive strength of the polystyrene free foam is 0.65 MPa or more; and / or the tensile strength of the polystyrene free foam is 0.9 MPa or more; and / or the polystyrene free foam has a thermal conductivity of 0.04 W-m -1 • K -1 The following.

37. The polystyrene free foam of claim 36, wherein, The apparent density of the polystyrene free foam is 15-90 g / L; and / or the compressive strength of the polystyrene free foam is 0.75 MPa or more; and / or the tensile strength of the polystyrene free foam is 1 MPa or more; and / or the polystyrene free foam has a thermal conductivity of 0.038 W-m -1 • K -1 The following.

38. The polystyrene free foam of claim 37, wherein, The apparent density of the polystyrene free foam is 40-52 g / L.

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