Polypropylene composition as well as preparation method and application thereof

Abstract

The invention discloses a polypropylene composition as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials, the polypropylene composition comprises the following components in parts by weight: 100 parts of polypropylene resin, 2.8-8.2 parts of liquid crystal polymer, 4.5-11 parts of polyurethane elastomer, 2.8-5.2 parts of compatilizer, 0-2.2 parts of assistant and 0.08-1.1 parts of coloring pigment. The polypropylene resin is used as a matrix, and under the combined action of the liquid crystal polymer, the polyurethane elastomer and the compatilizer, the laser marking performance and the wear resistance of the polypropylene composition are remarkably improved, so that patterns after laser marking are continuous and stable, and the definition is good; the polypropylene composition provided by the invention can effectively improve the wear resistance of a marking area, is suitable for preparing household appliances, electronic products, lighting products and automobile parts, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a polypropylene composition, a preparation method thereof, and an application thereof. Background Art

[0002] Polypropylene (PP) has advantages such as chemical resistance, heat resistance, electrical insulation, high-strength mechanical properties, and good high-abrasion processing performance, and is widely used in fields such as automobiles, electronic appliances, construction, textiles, packaging, agriculture, forestry, fishery, and the food industry. In practical applications of polypropylene products, especially in the fields of household appliances and electronic products, in order to improve the identifiability and traceability of products, markings are usually required on their surfaces.

[0003] Laser marking is a marking method that uses a laser with a high energy density to locally irradiate a workpiece, causing the surface material to vaporize or undergo a chemical reaction with a color change, thereby leaving a permanent mark. It has advantages such as permanence, anti-counterfeiting, non-contact, wide applicability, high engraving accuracy, and high processing efficiency, and its application in plastic product marking has developed rapidly. However, not all polymers are suitable for laser marking. For example, polyolefins (such as polypropylene is a polymer that is difficult or even impossible to laser mark) because it cannot effectively absorb the laser of the corresponding wavelength to form a laser mark, basically does not absorb the energy of the laser beam, and cannot convert light energy into heat energy, and its laser marking performance is poor, generally only producing a fuzzy and almost unrecognizable mark. This limits the application of laser marking technology in the plastic field.

[0004] In order to improve the laser marking effect of polypropylene, the prior art usually adds laser marking agents, but the laser marking agents are expensive, and most of the laser marking agents are some organic or inorganic metal oxides, which affect the appearance effect of PP products. Generally speaking, there are two mechanisms for laser marking of polyolefins, namely high-temperature carbonization and expansion foaming, both of which achieve the purpose of marking by destroying the surface material through different laser energies. However, in the marked area after laser marking, due to laser irradiation, the material changes, and the wear resistance of the marked area after laser marking drops significantly, making it difficult to meet the actual use requirements.

[0005] In view of this, the present application is proposed. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a polypropylene composition, a preparation method thereof, and an application thereof. The laser marking performance and wear resistance of the polypropylene composition are such that the pattern after laser marking is continuous, stable, has good clarity, and can effectively improve the wear resistance of the marked area.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A polypropylene composition comprising the following components in parts by weight: 100 parts of polypropylene resin, 2.8 to 8.2 parts of liquid crystal polymer, 4.5 to 11 parts of polyurethane elastomer, 2.8 to 5.2 parts of compatibilizer, 0 to 2.2 parts of auxiliary agent, 0.08 to 1.1 parts of coloring pigment.

[0009] The present invention creatively combines the above-mentioned raw materials. With polypropylene resin as the matrix, under the combined action of liquid crystal polymer, polyurethane elastomer and compatibilizer, the laser marking performance and wear resistance of the polypropylene composition are significantly improved, making the pattern after laser marking continuous, stable and clear. Moreover, the polypropylene composition of the present invention can effectively improve the wear resistance of the marked area. The polypropylene composition is applicable to the preparation of household appliances, electronic products, lighting products and automotive parts, and has broad application prospects.

[0010] The inventors of the present invention have found through research that liquid crystal polymer (abbreviation: LCP) has high mechanical strength, which helps to improve the wear resistance of PP products after being laser marked. However, the compatibility between LCP and PP system is poor. Especially after being irradiated by laser, phase separation is likely to occur, and the clarity (or stability) of laser marking is poor.

[0011] Based on this, the present invention creatively adds polyurethane elastomer to the system of the present invention. Through the combined use of polyurethane elastomer and LCP, polyurethane elastomer helps to improve the compatibility between PP and LCP, effectively improves the stability of the polypropylene composition under laser, further improves the wear resistance of the marked area, enables LCP to exert its excellent thermal stability and thermal conductivity, quickly converts laser energy into heat energy, improves the absorption of laser performance, reduces the heat affected zone during the laser marking process, and improves the marking clarity. At the same time, in the presence of the polyurethane elastomer, polyurethane has various groups such as ester group and amino group, and LCP has an aromatic structure. LCP, polyurethane and PP can combine to form a three-dimensional cross-linked network, which improves the absorption of laser energy and effectively improves the laser marking performance and the wear resistance of the marked area.

[0012] Among them, the dosage of the liquid crystal polymer is 2.8 to 8.2 parts, for example, it can be 2.8 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.2 parts or the range composed of any two of these values.

[0013] Preferably, the dosage of the liquid crystal polymer is 3 to 8 parts.

[0014] Among them, the dosage of the polyurethane elastomer is 4.5 to 11 parts, for example, it can be 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts, 10.5 parts, 11 parts or the range composed of any two of these values.

[0015] Preferably, the dosage of the polyurethane elastomer is 5 to 10 parts.

[0016] Among them, the dosage of the compatibilizer is 2.8 to 5.2 parts, for example, it can be 2.8 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.2 parts or the range composed of any two of these values.

[0017] Preferably, the dosage of the compatibilizer is 3 to 5 parts.

[0018] Among them, the dosage of the auxiliary agent is 0 to 2.2 parts, for example, it can be 0 part, 0.2 part, 0.5 part, 0.8 part, 1 part, 1.2 part, 1.5 part, 1.8 part, 2 parts, 2.2 parts or the range composed of any two of these values.

[0019] Preferably, the dosage of the auxiliary agent is 0 to 2 parts.

[0020] Among them, the dosage of the coloring pigment is 0.08 to 1.1 parts, for example, it can be 0.08 part, 0.1 part, 0.2 part, 0.4 part, 0.5 part, 0.6 part, 0.8 part, 1 part, 1.1 part or the range composed of any two of these values.

[0021] Preferably, the dosage of the coloring pigment is 0.1 to 1 part.

[0022] Among them, in the polypropylene composition of the present invention, the weight percentage content of the polypropylene resin is not less than 70%.

[0023] Preferably, the weight percentage content of the polypropylene resin is 70 to 90%, for example, it can be 70%, 72%, 75%, 76%, 78%, 80%, 84%, 85%, 88%, 90% or the range composed of any two of these values.

[0024] Preferably, the polypropylene resin has a melt flow rate of 3 to 150 g / 10 min at 230 °C / 2.16 kg according to the ISO1133-2011 method. For example, it can be 3 g / 10 min, 5 g / 10 min, 8 g / 10 min, 10 g / 10 min, 20 g / 10 min, 30 g / 10 min, 40 g / 10 min, 50 g / 10 min, 60 g / 10 min, 70 g / 10 min, 80 g / 10 min, 90 g / 10 min, 100 g / 10 min, 110 g / 10 min, 120 g / 10 min, 130 g / 10 min, 140 g / 10 min, 150 g / 10 min or a range composed of any two of these values.

[0025] Preferably, the polypropylene resin has a melt flow rate of 5 to 100 g / 10 min at 230 °C / 2.16 kg.

[0026] Preferably, the polypropylene resin has a melt flow rate of 10 to 60 g / 10 min at 230 °C / 2.16 kg.

[0027] Preferably, the polypropylene composition comprises the following components in parts by weight: 100 parts of polypropylene resin, 3 to 8 parts of liquid crystal polymer, 5 to 10 parts of polyurethane elastomer, 3 to 5 parts of compatibilizer, 0 to 2 parts of auxiliary agent, 0.1 to 1 part of coloring pigment. Especially when the dosage of each raw material is within this range, the compatibility is better. Under the combined action of each component, the laser marking performance and the wear resistance of the marked area are further improved.

[0028] Preferably, the polypropylene composition comprises the following components in parts by weight: 100 parts of polypropylene resin, 5 to 6.5 parts of liquid crystal polymer, 6.5 to 8 parts of polyurethane elastomer, 3 to 5 parts of compatibilizer, 0 to 2 parts of auxiliary agent, 0.1 to 1 part of coloring pigment.

[0029] Preferably, the melting point of the liquid crystal polymer is 270 to 380 °C. For example, it can be 270 °C, 280 °C, 290 °C, 300 °C, 310 °C, 320 °C, 330 °C, 340 °C, 350 °C, 360 °C, 370 °C, 380 °C or a range composed of any two of these values. In the present invention, the melting point of the liquid crystal polymer is controlled within the above range, so that the LCP can remain stable at a relatively high temperature. After laser marking, the marked area can be quickly cooled and remain stable, reducing the heat affected area, thereby improving the clarity and wear resistance of the mark.

[0030] Preferably, the melting point of the liquid crystal polymer is 338 to 355 °C. Especially when the melting point of the liquid crystal polymer is within this range, the laser marking performance and the wear resistance can be further improved.

[0031] Among them, the method for testing the melting point (Tm) of the liquid crystal polymer is as follows: using a differential scanning calorimeter for testing, with a heating rate of 20 °C / min, heating to 30 °C above the melting point, holding for 5 min, then cooling to room temperature at 20 °C / min, and then heating to 30 °C above the melting point at 20 °C / min. The temperature corresponding to the melting peak of the second heating curve is taken as the melting point.

[0032] Among them, the differential scanning calorimeter can be selected from the DSC 200F3 differential scanning calorimeter of NETZSCH company.

[0033] Preferably, the melt viscosity of the liquid crystal polymer is 8 - 40 Pa·s. For example, it can be 8 Pa·s, 10 Pa·s, 15 Pa·s, 20 Pa·s, 25 Pa·s, 30 Pa·s, 35 Pa·s, 40 Pa·s or the range composed of any two of these values.

[0034] Among them, the method for testing the melt viscosity of the liquid crystal polymer is as follows: using a capillary rheometer, according to the ISO11443 standard, at Tm (Tm is the melting point of the liquid crystal polymer) + 15 °C, 1000 s -1 under the conditions measured.

[0035] Preferably, the liquid crystal polymer includes at least one of liquid crystal polyester, liquid crystal polyurethane, and liquid crystal polyamide.

[0036] Preferably, the liquid crystal polymer includes liquid crystal polyester.

[0037] Preferably, the glass transition temperature of the polyurethane elastomer is -75 to -35 °C. For example, it can be -75 °C, -70 °C, -60 °C, -55 °C, -50 °C, -45 °C, -40 °C, -35 °C or the range composed of any two of these values. By controlling the glass transition temperature of the polyurethane elastomer within the above range, the compatibility of the polyurethane elastomer with LCP and PP is better. The three-dimensional cross-linked network formed by the polyurethane elastomer, LCP, and PP has a better absorption effect on laser energy, making the laser marking stability of the material better, generating sufficient thermal effects during laser marking, improving the clarity of the marked pattern, especially the clarity of the pattern edge, and improving the wear resistance of the marked area.

[0038] Among them, the glass transition temperature refers to the temperature at which the polyurethane elastomer changes from a glassy state to a highly elastic state. It is a property of amorphous polymer materials and a macroscopic manifestation of the transformation of polymer motion forms, which affects the service performance and processing performance of the materials. The test method for the glass transition temperature of the polyurethane elastomer of the present invention is as follows: The dynamic mechanical loss (DMA) method is used to test the glass transition temperature. The test specimen is an injection-molded specimen with a size of 80×10×4 mm. The three-point bending method is used for testing. The test points are the exact middle and both ends. It is cooled with liquid nitrogen, the temperature range is -100 to 100 °C, the heating rate is 10 °C / min, and the test frequency is 1 Hz.

[0039] Among them, the instrument used for the glass transition temperature of the polyurethane elastomer can be DMA242E produced by NETZSCH.

[0040] Preferably, the glass transition temperature (Tg) of the polyurethane elastomer is -60 to -48 °C. Especially when the temperature of the polyurethane elastomer is controlled within this range, the laser marking performance and wear resistance can be further improved.

[0041] Preferably, the polyurethane elastomer includes at least one of polyester-type polyurethane and polyether-type polyurethane.

[0042] Preferably, the weight ratio of the liquid crystal polymer to the polyurethane elastomer is 1:(0.625 - 3.4). For example, it can be 1:0.625, 1:1, 1:1.25, 1:1.5, 1:1.75, 1:2, 1:2.25, 1:3, 1:3.4 or the range composed of any two of these values.

[0043] Preferably, the weight ratio of the liquid crystal polymer to the polyurethane elastomer is 1:(1 - 1.6). By controlling the weight ratio of the liquid crystal polymer to the polyurethane elastomer within this range, it helps to improve the absorption degree of laser energy during marking, quickly convert the laser energy into heat energy, reduce the heat affected zone during the laser marking process, generate sufficient thermal effects during laser marking, have a more ideal synergistic effect, and can further improve the laser marking performance and wear resistance.

[0044] Preferably, the compatibilizer is a polar monomer-grafted polypropylene, and the polar monomer includes at least one of glycidyl methacrylate, maleic anhydride, acrylic acid, and acrylate.

[0045] Preferably, the compatibilizer includes at least one of maleic anhydride-grafted polypropylene and glycidyl methacrylate-grafted polypropylene.

[0046] The present invention uses polar monomer-grafted polypropylene as a compatibilizer, which can increase the polarity of polypropylene, further improve the absorption of laser energy. The introduction of polar groups improves the migration performance of other components in the polypropylene substrate, improves the melt flowability and moldability of the melt, further improves the interfacial bonding force between LCP, polyurethane elastomer and PP, improves the clarity of the marking area, and further improves the wear resistance of the marking area.

[0047] Preferably, the compatibilizer includes glycidyl methacrylate-grafted polypropylene.

[0048] Among them, the polar monomer-grafted polypropylene mentioned in the present invention can be obtained by purchasing commercially or can be prepared by oneself through the prior art.

[0049] Exemplarily, the preparation method of the polar monomer-grafted polypropylene includes the following steps:

[0050] Mix the initiator, polar monomer and polypropylene evenly, and carry out reactive extrusion through a twin-screw extruder. The temperature range of the screw is 165-200°C to obtain the polar monomer-grafted polypropylene.

[0051] It should be noted that the grafting rate of the polar monomer can be controlled by controlling the ratio of the polar monomer to polypropylene.

[0052] Among them, the initiator includes common thermal initiators such as azobisisobutyronitrile, dicumyl peroxide, tert-butyl peroxide, potassium persulfate, ammonium persulfate, etc.

[0053] Among them, the dosage of the initiator is 0.2-2 wt% of polypropylene. For example, it can be 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, 2 wt% or the range composed of any two of these values.

[0054] Among them, the mass ratio of the polar monomer to polypropylene is (0.2-3):(97-99.8). For example, it can be 0.2:99.8, 0.5:99.5, 1:90, 2:98, 3:97.

[0055] Among them, the present invention can use infrared spectroscopy and acid-base neutralization titration to test the grafting rate of the polar monomer. Taking maleic anhydride and glycidyl methacrylate as polar monomers respectively as examples, the test method of the grafting rate of the polar monomer is exemplarily described below.

[0056] Exemplarily, the grafting rate of maleic anhydride can be determined by infrared spectroscopy: Use a Fourier transform infrared spectrometer to test the infrared spectral characteristic absorption peaks of a sample with a fixed thickness, and the grafting rate of maleic anhydride can be calculated by comparing the ratio of the absorbance intensities of the carbonyl group and the methylene group.

[0057] Exemplarily, the grafting rate of glycidyl methacrylate can be determined by acid-base neutralization titration: Dissolve PP-g-GMA in 70 mL of hot xylene (above 110 °C), add 4 mL of 0.1 mol / L trichloroacetic acid xylene solution, reflux at 130 - 135 °C for 90 min to fully open the epoxy groups on GMA, titrate with 0.05 mol / L KOH methanol solution, use phenolphthalein as the indicator, and calculate the grafting rate according to the amount of KOH methanol solution consumed. The grafting rate Gd = 142.15*(V 0 -V)*c / (1000*m), where V 0 is the volume (mL) of KOH-methanol solution consumed for titrating ungrafted PP, V is the volume (mL) of KOH-methanol solution consumed for titrating grafted PP, c is the molar concentration of KOH, m is the mass of the titrated PP-g-GMA, and 142.15 is the molecular weight of GMA.

[0058] Preferably, the grafting rate of the polar monomer in the polar monomer-grafted polypropylene is 0.2 - 2 wt%, for example, it can be 0.2 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, 2 wt% or the range composed of any two of these values.

[0059] Preferably, the grafting rate of the polar monomer in the polar monomer-grafted polypropylene is 0.5 - 1 wt%.

[0060] Preferably, the auxiliary agent includes at least one of an antioxidant and a light stabilizer.

[0061] Preferably, the antioxidant includes at least one of thioester antioxidants, hindered phenol antioxidants, hydroxylamine antioxidants, phosphite antioxidants, and phosphate antioxidants.

[0062] Preferably, the thioester antioxidant includes at least one of dialkyl thiodipropionate or pentaerythritol tetrakis(3-laurylthiopropionate).

[0063] Preferably, the hindered phenol antioxidant includes at least one of pentaerythritol tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl) propionate], or 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane.

[0064] Preferably, the hydroxylamine antioxidant includes bis(octadecyl) hydroxylamine.

[0065] Preferably, the phosphite antioxidant includes at least one of tris(2,4-di-tert-butylphenyl) phosphite and pentaerythritol bis(di-2,4-tert-butylphenyl) diphosphite.

[0066] Preferably, the phosphate antioxidant includes bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate.

[0067] Preferably, the light stabilizer includes at least one of hindered amine light stabilizers, triazine light stabilizers, benzotriazole light stabilizers, and benzophenone light stabilizers.

[0068] Among them, representative hindered amine light stabilizers include at least one of UV-622, UV-944, UV-3853, and UV-123.

[0069] Among them, representative triazine light stabilizers include at least one of UV-236 and UV-237.

[0070] Among them, representative benzotriazole light stabilizers include at least one of UV234, Riasorb UV-326, UV-328, UV-P, UV384-2, and UV-360.

[0071] Among them, representative benzophenone light stabilizers include at least one of UV-531 and UV-928.

[0072] Preferably, the coloring pigment includes at least one of carbon black, titanium dioxide, aniline black, azo black, copper chromite black, iron chromite black, zinc sulfide, antimony white, tin oxide, bismuth vanadate yellow, quinophthalone yellow, 1-hydroxy-4-p-toluidinoanthraquinone, 1,4-bis[(2,6-diethyl-4-methylphenyl)amino]-9,10-anthraquinone, 1,4-bis[(2,4,6-trimethylphenyl)amino]-9,10-anthraquinone, 14H-phenyl[4,5]isoquinolino[2,1-a]naphthodiazepin-14-one.

[0073] Preferably, the coloring pigment includes at least one of carbon black and titanium dioxide.

[0074] Preferably, the polypropylene composition comprises the following components in parts by weight: 100 parts of polypropylene resin, 3 - 8 parts of liquid crystal polymer, 5 - 10 parts of polyurethane elastomer, 3 - 5 parts of compatibilizer, 0 - 1 part of antioxidant, 0 - 1 part of light stabilizer, and 0.1 - 1 part of coloring pigment.

[0075] Preferably, the polyamide composition of the present invention may further include at least one of lubricant, mineral powder, antistatic agent, and flame retardant.

[0076] The polypropylene composition of the present invention may contain a lubricant, and suitable lubricants include at least one of hyperbranched polyester, stearate, ethylene bisstearamide, and polyethylene wax.

[0077] The polypropylene composition of the present invention may include mineral powder, and suitable mineral powders include but are not limited to calcium carbonate, mica, kaolin, magnesium hydroxide, boehmite, and combinations thereof.

[0078] The polypropylene composition of the present invention may include an antistatic agent, and suitable antistatic agents include but are not limited to zinc oxide, manganese dioxide, chromium trioxide, and combinations thereof.

[0079] The polypropylene composition of the present invention may include a flame retardant, and suitable flame retardants include but are not limited to brominated polymers (e.g., brominated polystyrene), metal dialkyl phosphites (e.g., aluminum tris(diethyl phosphite)), metal hydroxides (e.g., magnesium hydroxide), aromatic phosphates (e.g., resorcinol bis(diphenyl phosphate) and bisphenol A bis(diphenyl phosphate)), and combinations thereof.

[0080] The present invention also provides a method for preparing a polypropylene composition, comprising the following steps:

[0081] Mix all raw materials evenly according to the ratio, melt and extrude to granulate to obtain the polypropylene composition.

[0082] The present invention also provides a workpiece obtained by laser marking a workpiece made of the above-mentioned polypropylene composition.

[0083] The beneficial effects of the present invention are as follows: The present invention uses polypropylene resin as the matrix, and under the combined action of liquid crystal polymer, polyurethane elastomer, and compatibilizer, significantly improves the laser marking performance and wear resistance of the polypropylene composition, making the pattern after laser marking continuous, stable, and with good clarity. Moreover, the polypropylene composition described in the present invention can effectively improve the wear resistance of the marked area, and the polypropylene composition is suitable for preparing household appliances, electronic products, lighting products, and automotive parts, having broad application prospects. Specific Embodiments

[0084] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0085] In the present application, among the technical features described in an open-ended manner, it includes a closed technical solution composed of the listed features, as well as an open technical solution containing the listed features.

[0086] In the present application, regarding the numerical range, unless otherwise specified, the above numerical range is considered continuous and includes the minimum and maximum values of this range, as well as each value between such minimum and maximum values. Further, when the range refers to an integer, it includes each integer between the minimum and maximum values of this range. In addition, when providing multiple ranges to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0087] The raw materials used in the examples and comparative examples are described as follows:

[0088] Polypropylene resin - 1: Purchased from Sinopec, grade PP EP300M.

[0089] Polypropylene resin - 2: Purchased from Sinopec, grade BX3800.

[0090] Liquid crystal polymer - 1: Purchased from Zhuhai Wantong Special Engineering Plastics, model Vicryst R8500, melting point Tm is 338 °C.

[0091] Liquid crystal polymer - 2: Purchased from Zhuhai Wantong Special Engineering Plastics, model Vicryst R800, melting point Tm is 355 °C.

[0092] Liquid crystal polymer - 3: Purchased from Zhuhai Wantong Special Engineering Plastics, model Vicryst R8000, melting point Tm is 280 °C.

[0093] Liquid crystal polymer - 4: Purchased from Zhuhai Wantong Special Engineering Plastics, model Vicryst R8200, melting point Tm is 370 °C.

[0094] Polyurethane elastomer - 1: Purchased from BASF, grade Elastollan C 95A, Tg is -60 °C.

[0095] Polyurethane elastomer - 2: Purchased from Chuangxin Chemical Industry, grade PC - 8, Tg is -48 °C.

[0096] Polyurethane elastomer - 3: Purchased from Bayer, grade Texin 1196, Tg is -75 °C.

[0097] Polyurethane elastomer - 4: Purchased from Chuangxin Chemical Industry, grade PC - 5, Tg is -35 °C.

[0098] PP - g - GMA - 1: Glycidyl methacrylate grafted polypropylene, grafting rate of glycidyl methacrylate is 1 wt%, self - made.

[0099] PP - g - GMA - 2: Glycidyl methacrylate grafted polypropylene, grafting rate of glycidyl methacrylate is 0.5 wt%, self - made.

[0100] PP - g - GMA - 3: Glycidyl methacrylate grafted polypropylene, grafting rate of glycidyl methacrylate is 0.2 wt%, self - made.

[0101] PP - g - GMA - 4: Glycidyl methacrylate grafted polypropylene, grafting rate of glycidyl methacrylate is 2 wt%, self - made.

[0102] PP - g - GMA - 5: Glycidyl methacrylate grafted polypropylene, grafting rate of glycidyl methacrylate is 1 wt%, Guangzhou Dongjin Plastic Technology Co., Ltd., grade PPG - 2321.

[0103] PP - g - MAH: Maleic anhydride grafted polypropylene, grafting rate of maleic anhydride is 1 wt%, purchased from Jia Yirong Co., Ltd., grade CMG - 5701.

[0104] Carbon black: Purchased from Cabot Corporation, grade M717.

[0105] Titanium dioxide: Purchased from Shanghai Yantai Industrial Co., Ltd., grade TR - 33.

[0106] Light stabilizer - 1: UV - 622, purchased from Lionon.

[0107] Light stabilizer - 2: UV - 234, purchased from Rianlon.

[0108] Antioxidant - 1: Antioxidant 1010, commercially available.

[0109] Antioxidant - 2: Antioxidant 168, commercially available.

[0110] Among them, the preparation methods of the above - mentioned PP - g - GMA - 1 to 4 all include the following steps:

[0111] Dissolve dicumyl peroxide (with a dosage of 1 wt% of polypropylene) in glycidyl methacrylate, then mix it evenly with polypropylene (the above - mentioned polypropylene resin - 1), and then extrude the mixture through a twin - screw extruder for reactive extrusion. The screw temperature range is 165 - 200 °C to obtain polypropylene grafted glycidyl methacrylate (PP - g - GMA).

[0112] By controlling the ratio of glycidyl methacrylate to polypropylene, the grafting rate of glycidyl methacrylate is controlled to obtain PP - g - GMA - 1 to 4 with different grafting rates.

[0113] Unless otherwise specified, the component raw materials used in the examples and comparative examples of the present invention are all commercially available raw materials, and the component raw materials used in each parallel experiment are of the same kind.

[0114] Examples 1 - 20, Comparative Examples 1 - 7

[0115] The formulations of the polypropylene compositions of Examples 1 - 20 and Comparative Examples 1 - 7 are shown in Table 1 and Table 2 (in parts by weight in the tables).

[0116] Among them, the preparation methods of the polypropylene compositions of Examples 1 - 20 and Comparative Examples 1 - 7 all include the following steps:

[0117] Mix each raw material evenly according to the ratio, and melt - extrude and pelletize at 180 - 220 °C to obtain the polypropylene composition.

[0118] Table 1

[0119]

[0120] Table 2

[0121]

[0122]

[0123] Performance test

[0124] Laser marking performance: The polypropylene obtained from the examples and comparative examples was combined and injection molded into a plastic square plate with dimensions of 100*50*2 mm. Then, an infrared laser with a wavelength of 1064 nm was used, the laser output power was 20 w, and the laser scanning speed was 1000 mm / s for laser marking. A straight line was marked parallel to the long side of the plastic square plate. Under a microscope, the difference between the widest and narrowest parts of the marked straight line was measured. The larger the difference, the worse the clarity and the worse the laser marking performance.

[0125] Abrasion resistance of the laser marking area: Under the same conditions as above, a square symbol (laser marking area) of 40*40 mm was laser marked, and then the scratch resistance of this area was tested (color difference after cross-hatching: tested according to the standard PV 3952 method, with a load of 10 N).

[0126] Table 3

[0127]

[0128]

[0129] As can be seen from Table 1, the polypropylene composition of the present invention has excellent laser marking performance and abrasion resistance, making the pattern after laser marking continuous, stable, with good clarity, and can effectively improve the abrasion resistance of the marked area. Among them, the difference between the widest and narrowest parts of the polypropylene composition is ≤0.04 mm, and the color difference is ≤0.39.

[0130] By comparing Comparative Example 2 with Comparative Examples 1-2, 4-7, it can be seen that the LCP and polyurethane elastomer of the present invention have a significant synergistic effect. Under their combined action, the laser marking performance and the abrasion resistance of the marked area are significantly improved.

[0131] By comparing Comparative Examples 1-4, it can be seen that by controlling the weight ratio of the liquid crystal polymer to the polyurethane elastomer to be 1:(1-1.6), the laser marking performance and the abrasion resistance of the marked area are further improved.

[0132] By comparing Comparative Examples 2, 6 with Examples 7-8, it can be seen that by controlling the melting point of the liquid crystal polymer to be 338-355 °C, the laser marking performance and the abrasion resistance of the marked area are further improved.

[0133] By comparing Comparative Examples 2, 9 with Examples 10-11, it can be seen that by controlling the glass transition temperature of the polyurethane elastomer to be -75 to -35 °C, the laser marking performance and the abrasion resistance of the marked area are further improved.

[0134] Comparing Comparative Example 2 and 12 with Examples 13 to 14, it can be seen that the grafting rate of the polar monomer in the polar monomer-grafted polypropylene of the present invention is 0.5 to 1 wt%, which further improves the laser marking performance and the wear resistance of the marked area.

[0135] Comparing Comparative Example 2 with Example 16, it can be seen that using glycidyl methacrylate-grafted polypropylene as a compatibilizer can further improve the laser marking performance and the wear resistance of the marked area.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polypropylene composition, characterized in that The invention comprises the following components in parts by weight: 100 parts of polypropylene resin, 2.8-8.2 parts of liquid crystal polymer, 4.5-11 parts of polyurethane elastomer, 2.8-5.2 parts of compatibilizer, 0-2.2 parts of auxiliary agent and 0.08-1.1 parts of coloring pigment.

2. The polypropylene composition according to claim 1, characterized in that The melting point of the liquid crystal polymer is 270 to 380°C, preferably 338 to 355°C.

3. The polypropylene composition according to claim 1, characterized in that The glass transition temperature of the polyurethane elastomer is -75 to -35°C, preferably -60 to -48°C.

4. The polypropylene composition according to claim 1, characterized in that The weight ratio of the liquid crystal polymer to the polyurethane elastomer is 1:(0.625-3.4), preferably 1:(1-1.6).

5. The polypropylene composition according to claim 1, characterized in that The compatibilizer is a polar monomer grafted with polypropylene, and the polar monomer includes at least one of glycidyl methacrylate, maleic anhydride, acrylic acid, and acrylic ester.

6. The polypropylene composition according to claim 1, characterized in that The coloring pigment includes at least one of carbon black, titanium dioxide, aniline black, azo black, copper chrome black, iron chrome black, zinc sulfide, antimony white, tin oxide, bismuth vanadate yellow, quinophthalone yellow, 1-hydroxy-4-p-toluaminoanthraquinone, 1,4-bis[(2,6-diethyl-4-methylphenyl)amino]-9,10-anthracene dione, 1,4-bis[(2,4,6-trimethylphenyl)amino]-9,10-anthracene dione, and 14H-phenyl[4,5]isoquinoline[2,1-A]perimetaben-14-one.

7. The polypropylene composition according to claim 5, characterized in that The grafting rate of the polar monomer in the polar monomer grafted polypropylene is 0.2-2 wt %, preferably 0.5-1 wt %.

8. The polypropylene composition according to claim 1, characterized in that The auxiliary agent includes at least one of an antioxidant and a light stabilizer.

9. The method for preparing the polypropylene composition according to any one of claims 1 to 8, characterized in that: The following steps are involved: The raw materials are mixed uniformly according to the proportion, melt-extruded and granulated to obtain a polypropylene composition.

10. A product, characterized in that: The product is obtained by laser marking a product made from the polypropylene composition according to any one of claims 1 to 8.

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