阅读说明：本技术 一种高流动低光泽苯乙烯基热塑性弹性体材料及制备方法 (High-fluidity low-gloss styrene-based thermoplastic elastomer material and preparation method thereof ) 是由 张德权 *** 于 2020-05-28 设计创作，主要内容包括：本发明属于聚合物材料改性和加工技术领域,具体涉及一种高流动低光泽苯乙烯基热塑性弹性体材料及其制备方法。本发明的原料包括如下重量份数的组分：PP树脂I：5-20份,PP树脂II：0.5-2份,苯乙烯嵌段共聚物：20-40份,填充油：20-50份,填料：10-20份,抗氧剂：0.3-0.6份,光稳定剂：0.6-1份,相容剂：2-5份,脱模剂：0.5-2份,色母粒：3-6份。本发明选用高流动性、低光泽的嵌段共聚PP树脂为主材,配合超高分子量的线型SEBS,并加入超高流动性PP树脂提高材料流动性,先将SEBS和石蜡油按一定比例预充油,再进行混料、挤出造粒,使制得的苯乙烯基热塑性弹性体材料兼具高流动性和低光泽度的优点,既满足注塑的工艺要求,又符合汽车内外饰件的产品外观需求。(The invention belongs to the technical field of modification and processing of polymer materials, and particularly relates to a high-fluidity low-gloss styrene-based thermoplastic elastomer material and a preparation method thereof. The raw materials of the invention comprise the following components in parts by weight: PP resin I: 5-20 parts of PP resin II: 0.5-2 parts of styrene block copolymer: 20-40 parts of filling oil: 20-50 parts of filler: 10-20 parts of antioxidant: 0.3-0.6 part of light stabilizer: 0.6-1 part of compatilizer: 2-5 parts of a release agent: 0.5-2 parts of color master batch: 3-6 parts. The invention selects the block copolymerization PP resin with high fluidity and low gloss as the main material, matches with the linear SEBS with ultra-high molecular weight, and adds the ultra-high fluidity PP resin to improve the fluidity of the material, firstly, the SEBS and the paraffin oil are pre-filled according to a certain proportion, then the materials are mixed and extruded for granulation, so that the prepared styrene-based thermoplastic elastomer material has the advantages of high fluidity and low gloss, thereby not only meeting the process requirements of injection molding, but also meeting the product appearance requirements of the interior and exterior trimming parts of the automobile.)

1. The high-flow low-gloss styrene-based thermoplastic elastomer material is characterized by comprising the following components in parts by weight:

PP resin I: 5-20 parts of

PP resin II: 0.5 to 2 portions of

Styrene block copolymer: 20-40 parts of

Filling oil: 20-50 parts of

Filling: 10-20 parts of

Antioxidant: 0.3 to 0.6 portion

Light stabilizer: 0.6 to 1 portion

A compatilizer: 2-5 parts of

Releasing agent: 0.5 to 2 portions of

Color master batch: 3-6 parts.

2. The high flow low gloss styrene-based thermoplastic elastomer material according to claim 1, wherein said PP resin I is a block copolymerized PP resin having a melt mass flow rate of 30 to 60g/10min at 230 ℃ under 2.16 KG.

3. The high flow low gloss styrene-based thermoplastic elastomer material as claimed in claim 1, wherein the PP resin II is an ultra-high flow PP resin having a melt mass flow rate of 1600-2000g/10min at 230 ℃ and 2.16 KG.

4. High flow low gloss styrene based thermoplastic elastomer material according to claim 1 or 2 or 3, characterized in that the mass ratio of PP resin I to PP resin II is (12-20): 1.

5. the high flow low gloss styrene-based thermoplastic elastomer material as claimed in claim 1, wherein said styrene block copolymer is ultra-high molecular weight SEBS having a linear structure.

6. The high flow low gloss styrene-based thermoplastic elastomer material according to claim 1, wherein the mass ratio of the styrene block copolymer to the extender oil is 3 (2-5).

7. The high flow low gloss styrene-based thermoplastic elastomer material according to claim 1 or 6, wherein the extender oil is a paraffin oil having a flash point of 240 ℃ or higher.

8. The high flow low gloss styrene-based thermoplastic elastomer material as claimed in claim 1, wherein said release agent is silicone master batch, wherein the silicone content is 70-85 wt%.

9. The high-flow low-gloss styrene-based thermoplastic elastomer material as claimed in claim 1, wherein the filler is talc, and the particle size of the talc is 2000-3000 mesh.

10. A process for the preparation of a high flow, low gloss styrene based thermoplastic elastomer material as claimed in any one of claims 1 to 9, comprising the steps of:

(1) pre-charging oil: weighing the component raw materials in proportion, mixing the styrene block copolymer and the filling oil in proportion, standing to ensure that the ethylene block copolymer fully absorbs oil to obtain a pre-filling oil mixture;

(2) mixing materials: putting the pre-oil-filled mixture and the rest other components into a mixing stirrer to be uniformly mixed;

(3) and (3) extruding and granulating: and adding all the mixed raw materials into a double-screw extruder, blending and granulating, and cooling, granulating and forming to obtain the styrene-based thermoplastic elastomer material with high fluidity and low gloss.

Technical Field

The invention belongs to the technical field of modification and processing of polymer materials, and particularly relates to a high-fluidity low-gloss styrene-based thermoplastic elastomer material and a preparation method thereof.

Background

The thermoplastic elastomer has various physical and mechanical properties of vulcanized rubber, such as high elasticity, aging resistance, oil resistance and the like, and excellent processing performance of plastics, and is widely applied to the industrial fields of automobile accessories and the like as a novel synthetic material. At present, a car sealing system mostly uses polyvinyl chloride (PVC) and thermoplastic vulcanized rubber (TPV) materials which have good elasticity and can play the roles of sealing, damping, waterproofing, dust prevention, sound insulation, decoration and the like in the car sealing system. PVC has low price, mature manufacturing process and extremely wide application, but has poor heat-resistant and weather-resistant performance, and the material contains halogen elements, has large smell, serious environmental pollution and great harm, and has the tendency of being replaced in the future. TPV has the advantages of low high-temperature compression set and good heat and weather resistance, is one of thermoplastic elastomer materials with the best elasticity, but has the problems of complex production process, higher cost and large smell. The high-temperature compression permanent deformation, heat resistance and weather resistance of the TPS are far superior to those of PVC, the material cost is lower than that of TPV, the production process flow is relatively simple, and compared with TPV, the TPS has higher cost performance, has the advantage of low odor, and has great application prospect in automobile static sealing systems, especially automobile interior trim parts.

The prior large internal and external decoration products such as automobile instrument panels, triangular windows and the like are mostly formed by injection molding, so that the materials are required to have good fluidity, and the products are required to keep lower glossiness. Poor flowability due to the use of TPS material after injection moldingAppearance defects such as tiger stripes and the like can be caused, in order to meet the requirements of an injection molding process, the flowability of a TPS (thermoplastic polystyrene) material is improved by increasing the content of PP (polypropylene) resin or filling oil in a material formula, so that the appearance defects of a product are improved, but the glossiness of the material can be improved simultaneously by the method, and the requirements of people on the appearance cannot be met in application occasions of manufacturing products with lower glossiness or replacing TPV (thermoplastic vulcanizate) materials. For this purpose, SiO is used after the flowability of the material has been increased₂The matting powder or other types of matting agents can reduce the glossiness of the product, for example, the silicone resin is added as an organic matting agent in the Chinese patent CN102875948A to prepare the styrene block thermoplastic elastomer with the matte effect, but the method can cause the mechanical properties of the material to be greatly reduced, especially the compression permanent deformation, so that the requirements of the product on the properties of the material cannot be met.

For automobile interior and exterior trim parts such as automobile instrument panels, triangular windows and the like, the glossiness of the material is reduced, so that the visual effect can be improved, and the visual effect is very important for guaranteeing the personal safety of drivers, and the automobile interior and exterior static sealing element series products are generally prepared by injection molding and have high requirements on the flowability of the material. Therefore, the technical difficulties to be solved at present are that the glossiness of the automobile static sealing element is higher or the glossiness and the fluidity of the material cannot be well balanced due to the fact that TPS is used for replacing TPV.

Disclosure of Invention

The invention aims to solve the technical problems and provides a high-flow low-gloss styrene-based thermoplastic elastomer material which can be widely applied to the series products of static sealing elements of the interior and exterior of automobiles.

The above object of the present invention is achieved by the following technical solutions:

a high-flow low-gloss styrene-based thermoplastic elastomer material comprises the following components in parts by weight:

PP resin I: 5-20 parts of

PP resin II: 0.5 to 2 portions of

Styrene block copolymer: 20-40 parts of

Filling oil: 20-50 parts of

Filling: 10-20 parts of

Antioxidant: 0.3 to 0.6 portion

Light stabilizer: 0.6 to 1 portion

A compatilizer: 2-5 parts of

Releasing agent: 0.5 to 2 portions of

Color master batch: 3-6 parts.

Preferably, the PP resin adopted by the invention is a high-fluidity block copolymerization PP resin, and the melt mass flow rate under the conditions of 230 ℃ and 2.16KG is 30-60g/10 min.

The block copolymerization PP resin used in the invention has higher fluidity and lower glossiness than the random copolymerization PP resin and the homopolymerization PP resin with the same fluidity. The crystal form arrangement of the random copolymerization PP resin is damaged by ethylene molecules, the spherulite structure is incomplete, and the crystal boundary is fuzzy, so that the scattering, refraction and absorption of the material to incident light are weakened, and the reflected light is enhanced; the length of the propylene segment in the block copolymerization PP resin is far greater than that of the ethylene segment, the propylene spherulite structure is not damaged, the spherulite size is large, the propylene spherulite structure has birefringence characteristics on polarized light, and the extinction phenomenon is generated due to the interference effect of the light, so that the glossiness of the material is greatly reduced. And the molecular chain integrity of the block copolymerization PP resin is good, the shear viscosity and the elasticity are low, and compared with random copolymerization PP resin and homopolymerization PP resin, the block copolymerization PP resin is not easy to cause extrusion thread distortion and has better processing performance.

Further preferably, the melt mass flow rate of the block copolymerized PP resin at 230 ℃ and 2.16KG is 50g/10 min.

Preferably, the PP resin II is an ultrahigh-fluidity PP resin, and the melt mass flow rate of the ultrahigh-fluidity PP resin at 230 ℃ and 2.16KG is 1600-2000g/10 min.

The ultrahigh-fluidity PP resin has extremely low viscosity, can be used as a fluidity regulator to improve the fluidity of the material, and compared with the conventional wax lubricant, the ultrahigh-fluidity PP resin does not influence the mechanical property of the material and can not be separated out. After the fluidity is improved, the replication capacity of the material on the skin pattern of the die is correspondingly improved, and the skin pattern depth of the surface of the product is increased, so that the influence of the ultrahigh-fluidity PP resin on the glossiness is small, the cost is relatively low, and the addition amount of the fluidity regulator is required to be controlled so that the surface of the product has a soft matte effect. Meanwhile, the higher the melt mass flow rate of the ultrahigh-fluidity PP resin is, the better the fluidity of the modified material is, and the surface gloss of the product is also increased. The inventors have also found that the improvement in flowability is minimal if the melt mass flow rate is lower, and that the effect on gloss increases when the melt mass flow rate is further increased. Therefore, the melt mass flow rate of the ultra-high fluidity PP resin used in the invention is 1600-2000g/10 min.

Further preferably, the melt mass flow rate of the ultra-high fluidity PP resin of the invention is 1900g/10min at 230 ℃ and 2.16 KG.

Further preferably, the mass ratio of the PP resin I to the PP resin II is (12-20): 1.

preferably, the styrene block copolymer used in the present invention is a hydrogenated styrene-butadiene block copolymer (SEBS) having a linear structure, wherein the molecular weight of the SEBS is 22 × 10⁴g/mol。

The SEBS is a polystyrene-polyethylene-polybutylene-polystyrene copolymer obtained by hydrogenating a styrene block copolymer, has a high-content 1, 2-vinyl structure, does not contain unsaturated double bonds in molecules, has better heat resistance, weather resistance and excellent aging resistance compared with an unhydrogenated styrene polymer, simultaneously has plasticity and high elasticity, and can be processed and used without vulcanization. Because the SEBS with a linear structure has larger mean square terminal distance and is easier to generate physical entanglement, and the SEBS with a star-shaped structure contains more diblock SEB and plays a certain plasticizing role in the SEBS, the linear SEBS has better mechanical property and rheological property than the star-shaped SEBS with the same molecular weight. The SEBS has higher molecular weight, higher styrene content, increased melt viscosity and better mechanical property.

More preferably, the SEBS with linear structure in the invention can be selected from SEBS YH503, SEBS6159, SEBS 6170, SEBS 2315, SEBS section 4099 with ultrahigh molecular weight, and the like.

The filling oil is paraffin oil with low viscosity and high flash point, and the flash point of the paraffin oil is more than or equal to 240 ℃. The filling oil used in the invention has the characteristic of low viscosity, ensures that the material has good processing fluidity, and can avoid slight degradation and surface gloss change caused by long-time retention of the material in a high-temperature screw rod in the injection molding process due to high flash point.

Preferably, the proportion of SEBS and paraffin oil in the invention is 3 (2-5).

When the elastomer material is prepared, the SEBS and the filling oil are fully mixed to carry out pre-oil filling, and then the SEBS and the filling oil are mixed with other residual components. The paraffin oil has a plasticizing effect on the SEBS, when the proportion of the paraffin oil is increased, the fluidity of the material is increased, but the compression permanent deformation is increased, and in order to ensure the balance of the fluidity and the compression permanent deformation of the thermoplastic elastic material, the processability and the mechanical property of the material are affected when the proportion of the SEBS and the paraffin oil is too small or too large during pre-oil filling.

Further preferably, the ratio of SEBS to paraffin oil in the present invention is 3: 4.

Preferably, the release agent is silicone master batch, wherein the content of silicone is 70-85 wt%. Silicone can effectively reduce the cohesiveness of the material between the extrusion process and the die, but if the content of organic silicon oxide in silicone is too high, the viscosity of the material can be increased, the dispersion is not facilitated, and certain organic carrier is added into silicone master batch, so that the defects of the performance of the traditional organic silicon auxiliary agent are overcome, the material is more easily dispersed, and the mixing effect is better. According to the invention, the silicone master batch with high molecular weight and high silicone content is used as the release agent, so that the heat-resistant and weather-resistant performance is better, the molding pressure of the material in the extrusion granulation and injection molding processes can be greatly reduced, and the injection molding and release effects of the product are improved.

More preferably, the silicone master batch of the present invention contains silicone 75 wt%.

Preferably, the filler of the invention is talcum powder, and the particle size of the talcum powder is 2000-3000 meshes. In the thermoplastic elastomer material, calcium carbonate is a common inorganic filler, and compared with granular calcium carbonate, the talcum powder used in the invention has lower glossiness due to the layered structure, and the granularity can be uniformly dispersed in the base material of oil-filled SEBS, so that the agglomeration of the talcum powder caused by too high mesh number can be avoided, and the appearance problems such as rough appearance of the product caused by too large grain diameter can be avoided.

Further preferably, the particle size of the talcum powder is 2500 meshes.

Preferably, the compatilizer used in the invention is SEBS maleic anhydride grafted product (SEBS-g-MAH), and the grafting rate is 1.6-2.0%. Because the blending effect of the SEBS and the polar polymer is poor, the fusion grafting of the SEBS and the MAH is an effective method for solving the problem, on one hand, the compatibility between the oil-filled SEBS and PP resin and the talcum powder can be improved, the overall mechanical property of the material is improved, on the other hand, a certain polarity can be given to the material, and the adhesive force between a product formed by injection molding of the material and glue is improved. Under the action of SEBS-g-MAH, the release agent and the filler can be uniformly dispersed in the SEBS and PP resin matrix material, and the silicone is also beneficial to forming gel particles to ensure that the surface presents uniform and fine textures, the scattering effect of the surface of the material is enhanced, the glossiness is reduced, and the surface of the product has a good matte effect.

More preferably, the grafting ratio of the compatilizer SEBS-g-MAH is 1.7%.

Preferably, the antioxidant is a compound antioxidant consisting of at least two of hindered phenols, hindered amines and long-acting heat stabilizers. The invention adopts more than two antioxidants for compounding, can effectively improve the heat resistance, oxidation resistance and ageing resistance of the material, and leads the obtained thermoplastic elastomer to be widely applied to the interior and exterior trimming parts of the automobile.

Preferably, the hindered phenol antioxidant can be antioxidant 1010, antioxidant 1076, antioxidant 1024, etc.; the hindered amine antioxidant can be light stabilizers 622, 770, 944 and the like; the long-acting heat stabilizer can be antioxidant B215, B225, B900 and the like.

Preferably, the light stabilizer of the present invention is a novel hindered amine light stabilizer.

Preferably, the color master batch adopted by the invention takes polypropylene as a carrier and has a high-filling black color master batch, and no processing aids such as wax substances and the like are used as the carrier, so that the influence of the color master batch on the material performance and the glossiness is further reduced.

The invention also aims to provide a preparation method of the high-flow low-gloss styrene-based thermoplastic elastomer material, which comprises the following steps:

(1) pre-charging oil: weighing the component raw materials in proportion, mixing the SEBS and the filling oil in proportion, standing to ensure that the SEBS fully absorbs oil to obtain a pre-filling oil mixture;

(2) mixing materials: putting the pre-oil-filled mixture and the rest other components into a mixing stirrer to be uniformly mixed;

(3) and (3) extruding and granulating: and adding all the mixed raw materials into a double-screw extruder, blending and granulating, and cooling, granulating and molding to obtain the styrene-based thermoplastic elastomer material.

In order to avoid the phenomenon that the hardness and elasticity of the material are reduced due to the fact that filling oil is unevenly dispersed in a melt, the step of pre-filling oil is added before mixing, and the SEBS is enabled to fully absorb paraffin oil.

Preferably, the length-diameter ratio of the twin-screw extruder in the step (3) is 45-55:1, the diameter of the screw is 32-38mm, the temperature of the twin-screw extruder is set to be 170-.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention modifies on the basis of a common TPS formula, selects the block copolymerization PP resin with high fluidity and low gloss as a main material, matches with the PP resin with ultrahigh fluidity, properly improves the proportion of filling oil, and prepares the styrene-based thermoplastic elastomer material by pre-filling oil, mixing materials, extruding and granulating, and has the advantages of high fluidity and low gloss.

2. The invention adopts linear SEBS with ultrahigh molecular weight, has the characteristics of low compression set, low glossiness and good oil absorption, and is beneficial to balancing the fluidity and glossiness of the material.

3. The PP resin with ultrahigh fluidity can greatly improve the fluidity of the material, does not influence the mechanical property of the material and the appearance of the product, and ensures that the surface of the product has a matte effect similar to TPV.

4. The paraffin oil disclosed by the invention has the characteristics of low viscosity and high flash point, and the SEBS and the paraffin oil are pre-filled according to a certain proportion in the processing technology, so that the high fluidity of an injection molding material is ensured, the influence on the surface gloss and other mechanical properties is reduced, the injection molding process requirement is met, and the product appearance requirement of automobile interior and exterior ornaments is met.

5. The high-fluidity low-gloss styrene-based thermoplastic elastomer material disclosed by the invention is reasonable in formula, easy in raw material obtaining, higher in cost performance, simple in preparation process, less in environmental hazard and capable of being widely applied to the series products of static sealing elements of automobile interiors and exteriors.

Detailed Description

The technical solution of the present invention is further described and illustrated by the following specific examples. The raw materials used in the examples of the present invention are those commonly used in the art, and the methods used in the examples are those conventional in the art, unless otherwise specified. It should be understood that the specific embodiments described herein are merely to aid in the understanding of the invention and are not intended to limit the invention specifically.

A high-flow low-gloss styrene-based thermoplastic elastomer material comprises the following components in parts by weight:

PP resin I: 5-20 parts of

PP resin II: 0.5 to 2 portions of

Styrene block copolymer: 20-40 parts of

Filling oil: 20-50 parts of

Filling: 10-20 parts of

Antioxidant: 0.3 to 0.6 portion

Light stabilizer: 0.6 to 1 portion

A compatilizer: 2-5 parts of

Releasing agent: 0.5 to 2 portions of

Color master batch: 3-6 parts.

The high-flow low-gloss styrene-based thermoplastic elastomer material in the embodiment of the invention is prepared by the following method:

(1) pre-charging oil: weighing raw materials in proportion, mixing SEBS and paraffin oil in proportion of 3 (2-5), standing for more than 4h to ensure that the SEBS fully absorbs oil to obtain a pre-filling oil mixture;

(2) mixing materials: putting the pre-oil-filled mixture and the rest other components into a low-speed mixer to be uniformly mixed;

(3) and (3) extruding and granulating: and adding all the mixed raw materials into a double-screw extruder for blending and granulation, wherein the length-diameter ratio of the double-screw extruder is 52:1, the diameter of a screw is 36mm, the temperature of the double-screw extruder is set to be 170-200 ℃, the rotating speed of a main machine is 300-400rpm, and strips extruded by a die are cooled and granulated and formed through a water tank to prepare the styrene-based thermoplastic elastomer material.