High-toughness high-transparency polypropylene thin-wall injection molding material and preparation method thereof

Abstract

The application relates to the technical field of polypropylene plastics, and is a kind of high-toughness high-transparency polypropylene thin-wall injection molding plastic and a preparation method thereof; the raw materials of the former include polypropylene, a molecular weight regulator, a nucleating agent and a compounded antioxidant; the molecular weight regulator, the nucleating agent, the antioxidant and the polypropylene are mixed in a high-speed mixer to obtain a premix, and then the premix is subjected to melt blending, extrusion and granulation through a double-screw extruder to obtain the high-toughness high-transparency polypropylene thin-wall injection molding plastic. By adding the additives to the polypropylene powder, the mechanical properties of the polypropylene are improved, the prepared high-toughness high-transparency polypropylene thin-wall injection molding plastic has high strength and sufficient toughness, and meets the regulations of national standards.

Description

Technical Field

[0001] This invention relates to the field of polypropylene plastics technology, specifically a high-toughness, high-transparency polypropylene thin-wall injection molding compound and its preparation method. Background Technology

[0002] When producing thin-walled injection-molded polypropylene, the mold cavity dimensions are more demanding than those of ordinary injection molding, thus requiring higher melt flow rates. Therefore, based on processing technology and product requirements, thin-walled injection molding materials generally require a melt flow index of 60 g / 10 min or higher, a flexural modulus of ≥1600 MPa, and a tensile yield strength of ≥35 MPa, among other performance requirements.

[0003] Currently, the main methods for obtaining high melt flow index polypropylene thin-wall injection molding materials are the hydrogen conditioning method and the controlled rheology method. The hydrogen conditioning method is simple; during the polymerization of propylene monomers into polypropylene macromolecular chains, hydrogen is used as a molecular weight regulator to reduce the length of the polypropylene molecular chains, thereby obtaining a higher melt flow index. Its advantage is that by increasing the proportion of hydrogen, the reaction activity is terminated without introducing other impurities. However, the range of adjustable polypropylene melt flow index is limited. When the melt flow index exceeds 40 g / 10 min, it becomes difficult to produce thin-wall injection molding materials using the hydrogen conditioning method, severely limiting its application areas.

[0004] Controlled rheology (CR) is a simple and low-cost process. During degradation, peroxides are thermally decomposed into two oxygen-containing free radicals at relatively low temperatures. These oxygen free radicals attack the hydrogen atoms on the tertiary carbons of polypropylene, causing β-chain scission and degrading the polypropylene into two short-chain structures. After controlled degradation modification, the molecular chains of polypropylene become shorter, the relative molecular mass decreases, the molecular weight distribution narrows, the melt index increases, and the fluidity is enhanced. CR can be used to flexibly produce polypropylene-specific materials of different grades, and compared with hydrogen modification, it can reduce the generation of transition materials.

[0005] Chinese patent document CNl07383584 A discloses a high-rigidity, high-modulus, thin-walled injection-molded polypropylene material, which is formulated from the following components in parts by weight: 100 parts of polypropylene prepared by hydrogen modification as the base resin, 0.03 to 0.15 parts of stiffening nucleating agent, 0.08 to 0.3 parts of antioxidant, 0.02 to 0.1 parts of halogen absorbent, and 0 to 0.06 parts of slip agent are added sequentially to a high-speed mixer and mixed at a speed of 1000 to 1500 rpm for 5 to 15 minutes to prepare a premix; the uniformly mixed premix is ​​fed into a twin-screw extruder for melt blending, the screw speed of the twin-screw extruder is 150 to 300 rpm, and the temperature of each heating zone of the barrel is 170°C to 200°C; the resulting blend is extruded into a sample, cooled and dried, and then granulated to obtain the crystallization-controlled thin-walled injection-molded polypropylene material. This invention employs a combination of hydrogen conditioning and degradation methods. During the polymerization of polypropylene, hydrogen is used as a molecular weight regulator, reacting with the active centers of the catalyst to terminate further polypropylene chain growth. This results in higher melt flow properties of the raw resin and improves the performance of the polypropylene powder used as a degradation-modified raw material. Under normal conditions, the cooling of polypropylene melt generates α-spherulites with weak intergranular bonding, easily leading to stress concentration and brittle fracture. By inhibiting α-crystals and inducing the formation of β-crystals, γ-crystals, or mesophases, the elongation at break can be increased to some extent, thereby improving its toughness. Therefore, after improving the flow properties of polypropylene powder using the hydrogen conditioning method, organic peroxides and other additives are added to the polypropylene resin for further modification, enhancing its flowability, mechanical, and optical properties, ultimately obtaining a high-rigidity, high-modulus, thin-walled injection-molded polypropylene material. The polypropylene material prepared by this method achieves tensile yield stress and flexural modulus of 38.0 MPa and 1800 MPa, respectively, demonstrating that the addition of stiffening nucleating agents effectively improves the rigidity of the polypropylene material. However, the notched impact strength of the polypropylene produced by this method is relatively low, reaching a maximum of only 1.4 KJ / m. 2 Thin-walled injection molding plastics lack toughness and are relatively brittle.

[0006] Chinese patent document CN114426738A discloses a high-flowability, high-rigidity, and low-warpage thin-walled polypropylene material for injection molding. This invention uses propylene and a small amount of ethylene as raw materials to produce a high melt index random copolymer polypropylene base resin via a hydrogenation process. By adding a primary antioxidant, an auxiliary antioxidant, a halogen absorber, and a nucleating agent, and mixing them uniformly in a specific ratio, the mixture is then melt-granulated in a twin-screw extruder to obtain a thin-walled polypropylene injection molding compound that meets the required specifications. The impact strength of this polypropylene can reach up to 2.2 KJ / m². 2The flexural modulus is 1782 MPa, the tensile yield stress is 36.2 MPa, and the lowest haze is 53.4%. It can be seen that the thin-walled injection molding compound produced by blending and modifying propylene and ethylene through hydrogenation and degradation methods has excellent rigidity and toughness, but its haze is high and its optical properties need to be improved. Summary of the Invention

[0007] This invention provides a high-toughness and high-transparency polypropylene thin-wall injection molding compound and its preparation method, which overcomes the shortcomings of the prior art and can effectively solve the problems of low strength and insufficient toughness of existing polypropylene thin-wall injection molding materials.

[0008] One of the technical solutions of this invention is achieved through the following measures: a high-toughness, high-transparency polypropylene thin-wall injection molding compound, wherein the raw materials, by weight, comprise...

[0009] 100 parts of polypropylene;

[0010] 0 to 5 parts of molecular weight regulator;

[0011] 0 to 1 part nucleating agent;

[0012] The compound antioxidant is 0 to 1 part.

[0013] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions:

[0014] The aforementioned polypropylene is a homopolymer polypropylene powder produced by the small bulk polymerization method. The homopolymer polypropylene powder is one of polypropylene 40, polypropylene 85, and polypropylene 150.

[0015] The aforementioned molecular weight regulator is one of molecular weight regulator NX101 and molecular weight regulator PP10-301.

[0016] The above-mentioned compound antioxidant consists of a primary antioxidant and a secondary antioxidant in a mass ratio of 1:1. The primary antioxidant is a hindered phenolic antioxidant, and the secondary antioxidant is a phosphite antioxidant.

[0017] The aforementioned hindered phenolic antioxidants are one of antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]), antioxidant 1076 (octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), and antioxidant 1098 (N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine).

[0018] The aforementioned phosphite antioxidants are one of antioxidant 168 (tris(2,4-di-tert-butylphenyl) phosphite), antioxidant 626 (bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite), and antioxidant 618 (pentaerythritol diphosphite dioctadecyl ester).

[0019] The above-mentioned nucleating agent is an organic nucleating agent, which is one of sorbitol nucleating agents and organophosphate nucleating agents.

[0020] The aforementioned organic nucleating agent is one of DMDBS nucleating agent, NA-21 nucleating agent, and HPN-20E nucleating agent.

[0021] The above-mentioned high-toughness and high-transparency polypropylene thin-wall injection molding compound, by weight, comprises the following raw materials:

[0022] Polypropylene 150 100 parts;

[0023] Molecular weight regulator NX101 1.2 parts;

[0024] Nucleating agent HPN-20E 0.7 parts;

[0025] Compound antioxidants

[0026] 0.08 parts of primary oxidant 1010;

[0027] 0.08 parts of auxiliary oxidant 168.

[0028] The above-mentioned high-toughness and high-transparency polypropylene thin-wall injection molding compound is obtained by the following method: First, the required amount of molecular weight regulator, nucleating agent, antioxidant and polypropylene are added to a high-speed mixer and mixed to obtain a premix; then, the obtained premix is ​​melt-blended, extruded and granulated by a twin-screw extruder to obtain the high-toughness and high-transparency polypropylene thin-wall injection molding compound.

[0029] The mixing time of the above-mentioned high-speed mixer is 5 to 10 minutes.

[0030] The screw speed of the above twin-screw extruder is set to 100 r / min to 140 r / min, the temperature of each heating zone of the barrel is 190℃ to 250℃, and the feed rate is 15% to 30%.

[0031] The second technical solution of the present invention is achieved through the following measures: a method for preparing high-toughness and high-transparency polypropylene thin-wall injection molding compound is carried out as follows: first, the required amount of molecular weight regulator, nucleating agent, antioxidant and polypropylene are added to a high-speed mixer and mixed to obtain a premix; then, the obtained premix is ​​melt-blended, extruded and granulated by a twin-screw extruder to obtain high-toughness and high-transparency polypropylene thin-wall injection molding compound.

[0032] The following are further optimizations and / or improvements to the second technical solution of the above invention:

[0033] The mixing time of the above-mentioned high-speed mixer is 5 to 10 minutes.

[0034] The screw speed of the above twin-screw extruder is set to 100 r / min to 140 r / min, the temperature of each heating zone of the barrel is 190℃ to 250℃, and the feed rate is 15% to 30%.

[0035] In summary, this invention improves the mechanical properties of polypropylene by adding additives to polypropylene powder, resulting in high-toughness and high-transparency polypropylene thin-wall injection molding compounds with high strength and sufficient toughness, meeting the requirements of national standards. Detailed Implementation

[0036] This invention is not limited to the following embodiments; specific implementation methods can be determined according to the technical solution of this invention and actual circumstances. Unless otherwise specified, all chemical reagents and chemical products mentioned in this invention are well-known and commonly used chemical reagents and chemical products in the prior art.

[0037] The present invention will be further described below with reference to embodiments:

[0038] Example 1: This high-toughness, high-transparency polypropylene thin-wall injection molding compound, the raw materials include by weight parts of:

[0039] 100 parts of polypropylene;

[0040] 0 to 5 parts of molecular weight regulator;

[0041] 0 to 1 part nucleating agent;

[0042] The compound antioxidant is 0 to 1 part.

[0043] Example 2: As an optimization of the above example, the polypropylene is a homopolymer polypropylene powder produced by the small bulk polymerization method, and the homopolymer polypropylene powder is one of polypropylene 40, polypropylene 85 and polypropylene 150.

[0044] The raw materials for this invention, polypropylene 40, polypropylene 85, and polypropylene 150, were all provided by China National Petroleum Corporation Urumqi Petrochemical Company.

[0045] Example 3: As an optimization of the above example, the molecular weight regulator is one of molecular weight regulator NX101 (dialkyl organic peroxide) and molecular weight regulator PP10-301 (cyclic ketone organic peroxide).

[0046] Example 4: As an optimization of the above example, the compound antioxidant is composed of a primary antioxidant and a secondary antioxidant in a mass ratio of 1:1. The primary antioxidant is a hindered phenolic antioxidant, and the secondary antioxidant is a phosphite antioxidant.

[0047] Example 5: As an optimization of the above examples, the hindered phenolic antioxidant is one of antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]), antioxidant 1076 (octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), and antioxidant 1098 (N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine).

[0048] Example 6: As an optimization of the above examples, the phosphite antioxidant is one of antioxidant 168 (tris(2,4-di-tert-butylphenyl) phosphite), antioxidant 626 (bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite), and antioxidant 618 (pentaerythritol diphosphite dioctadecyl ester).

[0049] Example 7: As an optimization of the above examples, the nucleating agent is an organic nucleating agent, which is one of sorbitol nucleating agent and organophosphate nucleating agent.

[0050] Example 8: As an optimization of the above examples, the organic nucleating agent is one of DMDBS nucleating agent (acetal nucleating agent), NA-21 nucleating agent (organophosphate nucleating agent) and HPN-20E nucleating agent (hindered phenolic nucleating agent).

[0051] Example 9: As an optimization of the above examples, high-toughness and high-transparency polypropylene thin-wall injection molding compound is obtained by the following method: First, the required amount of molecular weight regulator, nucleating agent, antioxidant and polypropylene are added to a high-speed mixer and mixed to obtain a premix; then, the obtained premix is ​​melt-blended, extruded and granulated by a twin-screw extruder to obtain high-toughness and high-transparency polypropylene thin-wall injection molding compound.

[0052] Example 10: As an optimization of the above examples, the mixing time of the high-speed mixer is 5 min to 10 min.

[0053] Example 11: As an optimization of the above example, the screw speed of the twin-screw extruder is set to 100 r / min to 140 r / min, the temperature of each heating zone of the barrel is 190°C to 250°C, and the feed rate is 15% to 30%.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] (1) The preparation method of the high toughness and high transparency polypropylene thin-wall injection molding compound of the present invention is convenient to operate and the process parameters can be flexibly adjusted during production to obtain polypropylene thin-wall injection molding compound with better performance.

[0056] (2) The high-toughness and high-transparency polypropylene thin-wall injection molding compound of the present invention improves the crystallization rate and density of the crystalline phase of polypropylene by adding additives to the degraded polypropylene granules, refines the grain size, and improves the mechanical properties of polypropylene. The resulting high-toughness and high-transparency polypropylene thin-wall injection molding compound has a strength of up to 1.80 KJ / m. 2 Up to 2.24 KJ / m 2 It has good toughness.

[0057] Example 12:

[0058] The high-toughness and high-transparency polypropylene thin-wall injection molding compound is made from 100 parts by weight of polypropylene (polypropylene 40), which is obtained by the following method: the required amount of polypropylene is first added to a high-speed mixer and mixed for 5 minutes, and then melt-blended, extruded and granulated by a twin-screw extruder to obtain the high-toughness and high-transparency polypropylene thin-wall injection molding compound; wherein, the screw speed of the twin-screw extruder is set to 100 r / min, the temperature of each heating zone of the barrel is 190℃, and the feed rate is 15%.

[0059] Example 13:

[0060] This high-toughness, high-transparency polypropylene thin-wall injection molding compound comprises, by weight, 100 parts of polypropylene (polypropylene 85), 5 parts of molecular weight regulator (molecular weight regulator PP10-301), 1 part of nucleating agent (NA-21 nucleating agent), and 1 part of compound antioxidant (antioxidant 1076 and antioxidant 626 in a 1:1 mass ratio). It is obtained as follows: First, the required amounts of molecular weight regulator, nucleating agent, and antioxidant are added to a high-speed mixer and mixed for 10 minutes to obtain a premix. Then, the obtained premix is ​​melt-blended, extruded, and granulated using a twin-screw extruder to obtain the high-toughness, high-transparency polypropylene thin-wall injection molding compound. The twin-screw extruder is set to a screw speed of 140 r / min, a barrel heating zone temperature of 250°C, and a feed rate of 30%.

[0061] Example 14:

[0062] This high-toughness, high-transparency polypropylene thin-wall injection molding compound comprises, by weight, 100 parts of polypropylene (polypropylene 150), 0.6 parts of molecular weight regulator (molecular weight regulator NX101), 0.5 parts of nucleating agent (HPN-20E nucleating agent), and 0.5 parts of compound antioxidant (main antioxidant (antioxidant 1098) and auxiliary antioxidant (antioxidant 618) in a 1:1 mass ratio). It is obtained as follows: First, the required amounts of molecular weight regulator, nucleating agent, and antioxidant are added to a high-speed mixer and mixed for 8 minutes to obtain a premix. Then, the obtained premix is ​​melt-blended, extruded, and granulated using a twin-screw extruder to obtain the high-toughness, high-transparency polypropylene thin-wall injection molding compound. The twin-screw extruder is set to a screw speed of 110 r / min, a barrel heating zone temperature of 220°C, and a feed rate of 25%.

[0063] Example 15:

[0064] This high-toughness, high-transparency polypropylene thin-wall injection molding compound comprises, by weight, 100 parts of polypropylene (polypropylene 150), 0.6 parts of molecular weight regulator (molecular weight regulator NX101), 0 parts of nucleating agent (HPN-20E nucleating agent), and 0.16 parts of compound antioxidants (0.08 parts of primary antioxidant 1010 and 0.08 parts of secondary antioxidant 168). It is obtained as follows: First, the required amounts of molecular weight regulator, nucleating agent, and antioxidant are added to a high-speed mixer and mixed for 10 minutes to obtain a premix. Then, the obtained premix is ​​melt-blended, extruded, and granulated using a twin-screw extruder to obtain the high-toughness, high-transparency polypropylene thin-wall injection molding compound. The twin-screw extruder is set with a screw speed of 110 r / min, a barrel heating zone temperature of 220°C, and a feed rate of 25%.

[0065] Example 16: The difference from Example 15 is that the weight of the raw material molecular weight regulator (molecular weight regulator NX101) is changed from 0.6 parts to 0.9 parts.

[0066] Example 17: The difference from Example 15 is that the weight of the raw material molecular weight regulator (molecular weight regulator NX101) is changed from 0.6 parts to 1.2 parts.

[0067] Example 18: The difference from Example 15 is that the weight of the raw material molecular weight regulator (molecular weight regulator NX101) is changed from 0.6 parts to 1.2 parts, and the nucleating agent (HPN-20E nucleating agent) is changed from 0 parts to 0.7 parts.

[0068] Example 19: The difference from Example 15 is that the weight of the raw material molecular weight regulator (molecular weight regulator NX101) is changed from 0.6 parts to 0 parts.

[0069] Example 20: The difference from Example 15 is that the weight of the raw material molecular weight regulator (molecular weight regulator NX101) is changed from 0.6 parts to 1.2 parts, and the nucleating agent (HPN-20E nucleating agent) is changed from 0 parts to 0.3 parts.

[0070] Example 21: The difference from Example 17 is that the 1.2 parts of the raw material molecular weight regulator (molecular weight regulator NX101) are changed to 0.9 parts of molecular weight regulator (molecular weight regulator PP10-301).

[0071] Example 22: The difference from Example 17 is that the raw material polypropylene 150 is changed to polypropylene 040.

[0072] Example 23: The difference from Example 17 is that the raw material polypropylene 150 is changed to polypropylene 085.

[0073] Example 24: The high-toughness, high-transparency polypropylene thin-wall injection molding compounds prepared in Examples 15 to 23 of the present invention were subjected to performance tests. The performance test results are shown in Tables 1 to 3. As can be seen from Table 1, the high-toughness, high-transparency polypropylene thin-wall injection molding compounds prepared in Examples 15 to 23 of the present invention can reach a strength of 1.80 KJ / m. 2 Up to 2.24 KJ / m 2 It has sufficient toughness and meets the requirements of national standards.

[0074] As can be seen from Examples 15, 16, 17 and 19 of the present invention in Table 1, under the same antioxidant addition amount, with the increase of the addition amount of molecular weight regulator NX101, the flow properties and mechanical properties of the polypropylene product were significantly improved, and the haze and yellow index were also reduced. By adding 1.2 parts of molecular weight regulator to modify and degrade polypropylene, the melt index increased from the initial 12.6 g / 10 min to 64.1 g / 10 min. Therefore, the optimal addition amount of molecular weight regulator in the raw material ratio of the present invention is 1.2 parts.

[0075] As can be seen from Examples 17, 18 and 20 of the present invention in Table 1, the addition of the nucleating agent greatly improves the mechanical properties of the polypropylene product, with a maximum impact strength of 2.24 KJ / m. 2 As the amount of nucleating agent added increases, the haze and yellow index performance are also improved. Therefore, the optimal amount of nucleating agent added in the formulation of this invention is 0.7 parts.

[0076] As can be seen from Examples 17, 18, and 21 of the present invention in Table 2, the molecular weight regulator PP10-301 exhibits superior degradation performance for polypropylene compared to NX101. When the addition amount is the same at 0.9 parts, the polypropylene melt index obtained using the molecular weight regulator PP10-301 is 6.2 g / 10 min higher than that obtained using the molecular weight regulator NX101. Therefore, the preferred molecular weight regulator for the raw materials in this invention is NX101.

[0077] As can be seen from Table 3, Examples 17, 22, and 23 of this invention, when polypropylene 150 is selected as the raw material, the molecular modifier NX101 has the best modification effect, resulting in the highest melt index of the high-toughness, high-transparency polypropylene thin-wall injection molding compound. Therefore, polypropylene 150 is the preferred raw material for this invention.

[0078] In summary, the high-toughness and high-transparency polypropylene thin-walled injection molded plastics obtained in Examples 15 to 23 of this invention all possess good mechanical properties, with strengths reaching up to 1.9 KJ / m². 2 Up to 2.24 KJ / m 2 It exhibits good toughness. Among them, the high-toughness and high-transparency polypropylene thin-wall injection molding compound obtained in Example 18 of this invention has the best mechanical properties, a high melt index, low haze and yellowness index, and the best optical properties.

[0079] In summary, this invention improves the mechanical properties of polypropylene by adding additives to polypropylene powder, resulting in high-toughness and high-transparency polypropylene thin-wall injection molding compounds with high strength and sufficient toughness, meeting the requirements of national standards.

[0080] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A high-toughness, high-transparency polypropylene thin-wall injection molding compound, characterized in that... Raw materials, by weight, include: 100 parts of polypropylene; 1.2 parts of molecular weight regulator; Nucleating agent 0.7 parts; 0 to 1 part of compound antioxidant; Among them, polypropylene is homopolymer polypropylene powder produced by small bulk polymerization, the homopolymer polypropylene powder is polypropylene 150, the nucleating agent is HPN-20E nucleating agent, the compound antioxidant is composed of a primary antioxidant and an auxiliary antioxidant in a mass ratio of 1:1, the primary antioxidant is a hindered phenolic antioxidant, the auxiliary antioxidant is a phosphite antioxidant, and the molecular weight regulator is molecular weight regulator NX101.

2. The high-toughness, high-transparency polypropylene thin-wall injection molding compound according to claim 1, characterized in that... The hindered phenolic antioxidant is one of antioxidant 1010, antioxidant 1076 and antioxidant 1098; and / or the phosphite antioxidant is one of antioxidant 168, antioxidant 626 and antioxidant 618.

3. The high-toughness, high-transparency polypropylene thin-wall injection molding compound according to claim 1 or 2, characterized in that... The following method is used to obtain a premix: First, the required amount of molecular weight regulator, nucleating agent, antioxidant and polypropylene are added to a high-speed mixer and mixed to obtain a premix; then, the obtained premix is ​​melt-blended, extruded and granulated by a twin-screw extruder to obtain a high-toughness and high-permeability polypropylene thin-wall injection molding compound.

4. The high-toughness, high-transparency polypropylene thin-wall injection molding compound according to claim 3, characterized in that... The mixing time of the high-speed mixer is 5 to 10 minutes; or / and the screw speed of the twin-screw extruder is set to 100 to 140 r / min, the temperature of each heating zone of the barrel is 190°C to 250°C, and the feed rate is 15% to 30%.

5. A method for preparing high-toughness, high-transparency polypropylene thin-wall injection molding compound according to any one of claims 1, 2, and 4, characterized in that... The process is as follows: First, add the required amount of molecular weight regulator, nucleating agent, antioxidant and polypropylene to a high-speed mixer and mix to obtain a premix; then, melt-blend, extrude and granulate the obtained premix through a twin-screw extruder to obtain high-toughness and high-permeability polypropylene thin-wall injection molding compound.

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