Molding compound for door and window decoration strip frame and preparation method thereof

Abstract

The invention discloses a molding compound for door and window decoration strip frames and a preparation method of the molding compound, and relates to the field of polymer composite materials. According to the molding compound for the door and window decoration strip frame, after various additives and matrix resin are premixed, the high-hardness aluminum oxide or barium sulfate powder and the filler are stirred and kneaded uniformly with the additives and the matrix resin, finally the reinforced glass fiber is kneaded and impregnated with the matrix resin, and air wrapped in the reinforced glass fiber is exhausted, so that the molding compound for the door and window decoration strip frame is prepared. Molding the prepared molding compound; according to the molding compound, the filler with fine particle size is used and comprises the high-hardness aluminum oxide, the barium sulfate powder and the unsaturated polyester resin with high crosslinking density, so that the hardness and the scratch resistance of a door strip product are improved, the coloring property is good, and a door strip formed by injection molding of the molding compound is attractive in appearance, thick and heavy in texture, uniform in color, scratch-resistant, good in adhesive force with primer and durable.

Description

Technical Field

[0001] The present invention relates to the field of polymer composite materials, and specifically to a molding compound for door and window decorative strip frames and a preparation method thereof. Background Art

[0002] Due to the diversity of customer requirements in the building door industry, the requirements for the shape, style and color of doors are diverse. For solid wood doors, the shape and style are generally assembled into various shapes by solid wood door strips or composite board door strips that are consistent with the color and texture of the door frame. Composite board doors are mainly formed in one time by molds or assembled by door strips. Among them, solid wood doors are relatively expensive and consume a large amount of wood. There are problems such as formaldehyde volatilization in the processing and assembly of composite boards. Currently, most high-end non-solid wood doors use formaldehyde-free molding compound composites (SMC) to press the entire door skin, and directly make imitation wood textures and molding structures on the door skin mold. Then, the door skin and the skeleton are assembled, and foaming materials are filled in the middle. Such doors have a thick texture, imitate wood grains, and have beautiful shapes.

[0003] However, since the door skin and the shape are integrally formed, special large molds are required, the equipment investment is large, and only one shape can be made with one mold. Therefore, some manufacturers use molds to produce standard door skins, and then use door strips with certain shapes as decorative strips to assemble various shapes. As shown below Figure 5 The door strip materials include PVC formed by pultrusion or composite board formed by compression molding, or SMC materials the same as the door skin formed by compression molding. Among them, PVC and composite board door strips have low hardness and are easily scratched during processing and use, affecting the appearance; moreover, their texture is relatively light and inconsistent with the texture of the main material of the door frame; in addition, it is necessary to adjust the color according to the color of the main material of the door frame. On the one hand, it is difficult to make the colors consistent, and on the other hand, the production and molding of materials of different colors will increase the complexity and cost of production; there are also problems such as low production efficiency in the compression molding process. In order to overcome the above problems, the present invention uses a molding compound that can be injection molded to prepare a molding compound for door and window decorative strip frames, which can form door frame decorative strips of various shapes and be used to combine with door skins to form various molding structures. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a molding compound for door and window decorative strip frames and a preparation method thereof.

[0005] One technical solution proposed by the present invention to solve the above technical problems is: a molding compound for door and window decorative strip frames, comprising the following components in mass percentage: 10-20% of mixed powder, 15-25% of matrix resin, 30-50% of filler, 1-5% of additive, and 10-20% of reinforcing fiber; the mixed powder comprises alumina powder and barium sulfate powder with a mass ratio of 5-8:3-8; the matrix resin comprises unsaturated polyester resin, polystyrene particles, butadiene-styrene copolymer particles and styrene; the additives comprise a curing agent, an internal mold release agent, a phase separation inhibitor, a viscosity reducer and inorganic color powder.

[0006] Preferably, the mass ratio of the all-cis-anhydride type unsaturated polyester resin, polystyrene particles, butadiene-styrene copolymer particles and styrene is 65-70:13-20:12:10; the polystyrene particles have a molecular weight of 300,000-400,000 and a particle size of 0.3-0.5 mm, and the butadiene-styrene copolymer has a molecular weight of 200,000-300,000 and a particle size of 0.3-0.5 mm.

[0007] Preferably, the dosage of the inhibitor is 14-16% of the mass of the all-cis-anhydride type unsaturated polyester resin; the dosage of the styrene is 40%-60% of the mass of the unsaturated polyester resin.

[0008] Preferably, the inhibitor is one or more of hydroquinone, methyl hydroquinone, and p-tert-butylcatechol.

[0009] Preferably, the particle size of the alumina powder is 1-10 μm; the particle size of the barium sulfate powder is 1-10 μm.

[0010] Preferably, the filler is one or more mixtures of calcium carbonate, aluminum hydroxide, and talc powder, and the filler particle size is 1-5 μm.

[0011] Preferably, the reinforcing fiber is short-cut glass fiber with a length of 3-12 mm.

[0012] Preferably, the mass ratio of the curing agent, internal mold release agent, phase separation inhibitor, viscosity reducer and inorganic color powder is 1-5:0.5-2:0.1-1:0.5-5:0.1-5; the curing agent is one of curing agent TBPB and curing agent TBPO; the internal mold release agent is a mixture of polydimethylsiloxane and polyphosphate with a mass ratio of 1-6:1; the phase separation inhibitor is one or a mixture of two of 1-methoxy-2-propyl acetate and 1-methoxy-1-propyl acetate; the viscosity reducer is polyphosphate; the inorganic color powder is an environmentally friendly inorganic color powder.

[0013] Preferably, the preparation method of the molding compound for door and window decorative strip frames comprises the following specific steps:

[0014] S1. Add the matrix resin and additives into the mixing kettle in sequence according to the ratio, stir at 500 - 1500 rpm for 5 - 8 min, then transfer it to a double-arm kneader, add alumina powder and barium sulfate powder, and evenly disperse the alumina and barium sulfate powders into the matrix resin by the differential rotation of the two stirring paddles in the kneader. The rotation speed of the active paddle is 20 - 30 rpm, the rotation speed ratio of the active paddle to the driven paddle is 1.5 - 2:1, and the stirring time is 5 - 8 min to obtain a resin paste.

[0015] S2. Put the filler into the kneader, start the kneader to knead the filler and the resin paste. The rotation speed of the active paddle is 20 - 30 rpm, the rotation speed ratio of the active paddle to the driven paddle is 1.5 - 2:1, and the stirring time is 20 - 30 min to stir evenly. Then add the reinforcing fiber and continue to knead and disperse. The rotation speed of the active paddle is 20 - 30 rpm, the rotation speed ratio of the active paddle to the driven paddle is 1.5 - 2:1, and the stirring time is 4 - 8 min to obtain the finished molding compound.

[0016] S3. After taking out the finished molding compound, put it into a tooling with a specified shape and compact it to discharge the air entrapped in the material, and then seal and package it to obtain the molding compound for the door and window decorative strip frame.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0018] The molding compound for the door and window decorative strip frame prepared by the present invention, after premixing various additives and the matrix resin, then stirring and kneading the high-hardness alumina or barium sulfate powder and the filler evenly with it, and finally kneading and impregnating the reinforcing glass fiber with it and discharging the entrapped air, is made into the molding compound for the door and window decorative strip.

[0019] The matrix resin includes unsaturated polyester resin, polystyrene particles, butadiene-styrene copolymer particles and styrene. The unsaturated polyester resin refers to the fully maleic anhydride type of unsaturated polyester resin. When preparing, fine-particle-size fillers including high-hardness alumina and barium sulfate powder are used with the matrix resin to improve the hardness and scratch resistance of the door strip products. The matrix resin includes unsaturated polyester resin, polystyrene particles, butadiene-styrene copolymer particles and styrene; the unsaturated polyester resin is prepared by the polycondensation dehydration reaction of dihydric alcohol and unsaturated dibasic anhydride to improve the hardness and scratch resistance of the door strip products; the unsaturated polyester resin is the fully maleic anhydride type of unsaturated polyester resin. This kind of unsaturated polyester resin has a high degree of unsaturation and a large crosslinking density, and the surface hardness of the molded products is high and more scratch-resistant.

[0020] By adjusting the fine particle size and high specific gravity fillers, high proportion filling can improve the density and texture of the product; using a viscosity reducer to lower the system viscosity and improve the flowability, enabling the molding compound to form long products over 800 mm. Adding a phase separation inhibitor to prevent material component separation and improve the material uniformity. Using a PS system and SBS composite low shrinkage system to improve the coloring performance of the material. Using a phosphoric acid polyester internal mold release agent, which has both polar and non-polar groups, can ensure product demolding without affecting the adhesion of subsequent painting or lacquering. Adding aluminum hydroxide as a flame retardant, which is halogen-free, non-toxic, safe and environmentally friendly. Description of the Drawings

[0021] Figure 1 It is the formaldehyde and acetaldehyde test of the molding compound for door and window decorative strip frames prepared in Example 3.

[0022] Figure 2 It is the formaldehyde and acetaldehyde test of the molding compound for door and window decorative strip frames prepared in Comparative Example 3.

[0023] Figure 3 It is the appearance of the molding compounds for door and window decorative strip frames prepared in the examples and comparative examples.

[0024] Figure 4 It is for the molding compounds for door and window decorative strip frames prepared in Example 2 and Comparative Example 2 after painting.

[0025] Figure 5 It is the shape assembled with door strips with a certain shape as decorative strips. Detailed Description of the Invention

[0026] The present invention will be specifically described below through examples. It is necessary to point out here that the following examples are only used to further illustrate the present invention and should not be construed as limiting the protection scope of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention according to the above content of the present invention. Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art.

[0027] To more clearly illustrate the method provided by the present invention, the following examples are used for detailed description. The test methods for each index of the molding compounds for door and window decorative strip frames prepared in the examples and comparative examples are as follows:

[0028] The test standard for formaldehyde and acetaldehyde is: ISO12219-2:2012.

[0029] Example 1

[0030] In the components of the molding compound for the door and window decorative strip frame in this embodiment, the mass ratio of unsaturated polyester resin, polystyrene particles, butadiene-styrene copolymer particles and styrene is 65:13:12:10. The particle size of the alumina powder is 5 μm; the particle size of the barium sulfate powder is 5 μm; the molecular weight of the polystyrene particles is 300,000 - 400,000, and the particle size is 0.3 mm. The molecular weight of the butadiene-styrene copolymer is 200,000 - 300,000, and the particle size is 0.3 mm; the reinforcing fiber is chopped glass fiber with a length of 3 mm; the internal mold release agent is a mixture of polydimethylsiloxane and polyphosphate with a mass ratio of 1:1; the phase separation inhibitor is one or a mixture of two of 1-methoxy-2-propyl acetate and 1-methoxy-1-propyl acetate; the viscosity reducer is polyphosphate; the inorganic color powder is an environmentally friendly inorganic color powder;

[0031] The preparation method of the molding compound for the door and window decorative strip frame in this embodiment is as follows:

[0032] S1. Mix ethylene glycol and unsaturated maleic anhydride at a molar ratio of 1.05:1, heat up to 180 °C, react until the acid value is 16 mgKOH / g, cool down to 140 °C, add the polymerization inhibitor hydroquinone and styrene. The dosage of the polymerization inhibitor is 50 ppm of the mass of the unsaturated polyester resin; the dosage of styrene is 40% of the mass of the unsaturated polyester resin to obtain the unsaturated polyester resin; add the matrix resin and additives to the mixing kettle in sequence, stir at 500 rpm for 5 min, then transfer to a double-arm kneader, add alumina powder and barium sulfate powder, and evenly disperse the alumina and barium sulfate powder into the matrix resin by the differential rotation of the two stirring paddles in the kneader. The rotation speed of the active paddle is 20 rpm, the rotation speed ratio of the active paddle to the driven paddle is 1.5:1, and the stirring time is 5 min to obtain the resin paste;

[0033] S2. Put the filler into the kneader, turn on the kneader to knead the filler and the resin paste. The rotation speed of the active paddle is 20 rpm, the rotation speed ratio of the active paddle to the driven paddle is 1.5:1, and the stirring time is 20 min to stir evenly. Then add the reinforcing fiber and continue to knead and disperse. The rotation speed of the active paddle is 20 rpm, the rotation speed ratio of the active paddle to the driven paddle is 1.5:1, and the stirring time is 4 min to obtain the finished molding compound;

[0034] S3. After taking out the finished molding compound, put it into a tooling of a specified shape, compact it, discharge the air trapped in the material, and seal and package it to obtain the molding compound for the door and window decorative strip frame.

[0035] Example 2

[0036] In the components of the molding compound for the door and window decorative strip frame in this embodiment, the mass ratio of unsaturated polyester resin, polystyrene particles, butadiene-styrene copolymer particles, and styrene is 68:17:12:10. The particle size of the alumina powder is 5 μm; the particle size of the barium sulfate powder is 5 μm; the molecular weight of the polystyrene particles is 300,000 - 400,000, and the particle size is 0.4 mm. The molecular weight of the butadiene-styrene copolymer is 200,000 - 300,000, and the particle size is 0.4 mm; the reinforcing fiber is chopped glass fiber with a length of 9 mm; the internal mold release agent is a mixture of polydimethylsiloxane and polyphosphate with a mass ratio of 3:1; the phase separation inhibitor is one or a mixture of two of 1-methoxy-2-propyl acetate and 1-methoxy-1-propyl acetate; the viscosity reducer is polyphosphate; the inorganic color powder is an environmentally friendly inorganic color powder;

[0037] The preparation method of the molding compound for the door and window decorative strip frame in this embodiment is as follows:

[0038] S1. Mix dipropylene glycol and maleic anhydride in a molar ratio of 1.15:1, heat up to 195 °C, react until the acid value is 19 mg KOH / g, cool down to 150 °C, add a polymerization inhibitor and styrene. The dosage of the polymerization inhibitor is 400 ppm of the mass of the unsaturated polyester resin; the dosage of the styrene is 50% of the mass of the unsaturated polyester resin to obtain the unsaturated polyester resin. Add the matrix resin and additives to the mixing kettle in proportion, stir at 1000 rpm for 6 min, then transfer to a double-arm kneader, add alumina powder and barium sulfate powder, and evenly disperse the alumina and barium sulfate powder into the matrix resin by the differential rotation of the two stirring paddles in the kneader. The rotation speed of the active paddle is 25 rpm, the rotation speed ratio of the active paddle to the driven paddle is 1.8:1, and the stirring time is 6 min to obtain a resin paste;

[0039] S2. Put the filler into the kneader, start the kneader to knead the filler and the resin paste. The rotation speed of the active paddle is 25 rpm, the rotation speed ratio of the active paddle to the driven paddle is 1.8:1, and the stirring time is 25 min to stir evenly. Then add the reinforcing fiber and continue to knead and disperse. The rotation speed of the active paddle is 25 rpm, the rotation speed ratio of the active paddle to the driven paddle is 1.8:1, and the stirring time is 6 min to obtain the finished molding compound;

[0040] S3. After taking out the finished molding compound, put it into a tooling of a specified shape, compact it to discharge the air entrapped in the material, and seal and package it to obtain the molding compound for the door and window decorative strip frame.

[0041] Example 3

[0042] In the components of the molding compound for the door and window decorative strip frame in this embodiment, the mass ratio of unsaturated polyester resin, polystyrene particles, butadiene-styrene copolymer particles, and styrene is 70:20:12:10. The particle size of the alumina powder is 10 μm; the particle size of the barium sulfate powder is 10 μm; the molecular weight of the polystyrene particles is 300,000 - 400,000, and the particle size is 0.5 mm. The molecular weight of the butadiene-styrene copolymer is 200,000 - 300,000, and the particle size is 0.5 mm; the reinforcing fiber is chopped glass fiber with a length of 12 mm; the internal mold release agent is a mixture of polydimethylsiloxane and polyphosphate with a mass ratio of 6:1; the phase separation inhibitor is 1-methoxy-1-propyl acetate; the viscosity reducer is polyphosphate; the inorganic color powder is an environmentally friendly inorganic color powder.

[0043] The preparation method of the molding compound for the door and window decorative strip frame in this embodiment is as follows:

[0044] S1. Mix diglycol and maleic anhydride in a molar ratio of 1.2:1, heat up to 210 °C, react until the acid value reaches 22 mg KOH / g, cool down to 160 °C, add an inhibitor and styrene. The dosage of the inhibitor is 700 ppm of the mass of the unsaturated polyester resin; the dosage of the styrene is 60% of the mass of the unsaturated polyester resin to obtain the unsaturated polyester resin. Add the matrix resin and additives to the mixing kettle in sequence, stir at 1500 rpm for 8 min, then transfer to a double-arm kneader, add alumina powder and barium sulfate powder, and evenly disperse the alumina and barium sulfate powder into the matrix resin by the differential rotation of the two stirring paddles in the kneader. The rotational speed of the active paddle is 30 rpm, the rotational speed ratio of the active paddle to the driven paddle is 2:1, and the stirring time is 8 min to obtain the resin paste.

[0045] S2. Put the filler into the kneader, start the kneader to knead the filler and the resin paste. The rotational speed of the active paddle is 30 rpm, the rotational speed ratio of the active paddle to the driven paddle is 2:1, and the stirring time is 30 min to stir evenly. Then add the reinforcing fiber and continue to knead and disperse. The rotational speed of the active paddle is 30 rpm, the rotational speed ratio of the active paddle to the driven paddle is 2:1, and the stirring time is 8 min to obtain the finished molding compound.

[0046] S3. After taking out the finished molding compound, put it into a tooling with a specified shape, compact it, discharge the air entrapped in the material, and seal and package it to obtain the molding compound for the door and window decorative strip frame.

[0047] Comparative Example 1

[0048] The preparation method of Comparative Example 1 is the same as that of Example 2. The difference between the molding compound for the door and window decorative strip frame and Example 2 is that the matrix resin is o-phthalic unsaturated polyester resin P71-90.

[0049] Comparative Example 2

[0050] The preparation method of Comparative Example 2 is the same as that of Example 2. The difference between the molding compound for the door and window decorative strip frame and that of Example 2 is that the mixed powder is not added.

[0051] Comparative Example 3

[0052] The preparation method of Comparative Example 3 is the same as that of Example 2. The difference between the molding compound for the door and window decorative strip frame and that of Example 2 is that the PVC pellets are injected into the mold through an injection molding machine for curing, cooling and shaping. The curing temperature is 170 °C and the time is 60 s.

[0053] Effect Example

[0054] The hardness, density, mechanical strength, surface tension, fluidity, and flame retardancy of Examples 1 to 3 and Comparative Examples 1 to 3 of the present invention were respectively tested, and door strips with dimensions of 813 * 51 * 5.7 mm were injection molded using a special door strip mold. Comparative Example 3 was extruded from PVC. At the same time, the appearance of the products was compared, the appearance of the products of Example 2 and Comparative Example 2 after painting was compared, and the formaldehyde and acetaldehyde volatiles of the products of Example 3 and the PVC of Comparative Example 3 were tested.

[0055] Table 1 is the table of the component weight fraction contents of the examples and comparative examples;

[0056] Table 2 is the performance test data of the examples and comparative examples;

[0057] Table 1

[0058] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Unsaturated polyester resin 65 65 70 70 65 Polystyrene particles 13 13 20 13 Butadiene-styrene copolymer particles 12 12 12 12 Styrene 10 10 10 10 Aluminum oxide powder 70 50 50 Barium sulfate powder 30 90 30 Aluminum hydroxide 100 100 100 100 Calcium carbonate 100 100 100 280 180 Internal mold release agent 0.5 1 2 1 1 Curing agent TBPB 1 5 Curing agent TBPO 2 2 2 Phase separation inhibitor 0.1 0.5 1 0.5 0.5 Inorganic color powder 1 3 5 3 3 Chopped glass fiber 80 80 80 80 80

[0059] Table 2

[0060] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Barcol hardness 70 65 67 50 45 5 Density 2.05 2.10 2.08 1.92 1.86 1.45 Flexural strength 130 126 153 121 110 62 Flexural modulus 13.2 13.0 13.9 12.2 12.5 3.6 Surface tension 40 41 42 36 35 36 Flowability 116 135 108 81 76 / Flame retardant 2mm V-0 2mm V-0 2mm V-0 HB 2mm V-0 Non-flame retardant

[0061] From the comparison of the performance data in Table 2, it can be seen that the molding compound prepared by the present invention, the hardness and density of the products are significantly better than those of the door strip products prepared from the PVC of Comparative Example 3, and also better than those of Comparative Example 1 and Comparative Example 2;

[0062] After premixing various additives and the matrix resin, the high-hardness alumina or barium sulfate powder and the filler are stirred and kneaded evenly with them, and finally the reinforcing glass fiber is kneaded and impregnated with them, and the air trapped in them is discharged to prepare a molding compound for the door and window decorative strip; therefore, the door frame decorative strip formed by the molding compound of the present invention has better wear resistance and scratch resistance, and the texture of the product is also thicker. At the same time, the surface tension is greater, which makes the adhesion between the primer and the substrate better after painting; the fluidity of the examples is better, longer products can be molded, and the flame retardancy of the examples is better and safer.

[0063] Obviously, the above embodiments are merely examples given to clearly illustrate the embodiments of the present invention, rather than limitations on the embodiments of the present invention. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the embodiments here. And these obvious changes or variations derived from the spirit of the present invention are still within the protection scope of the present invention.

Claims

1. A molding compound for door and window decorative strips, characterized in that: The invention comprises the following components in percentage by mass: 10-20% of mixed powder, 15-25% of matrix resin, 30-50% of filler, 1-5% of additive and 10-20% of reinforcing fiber; the mixed powder comprises aluminum oxide powder and barium sulfate powder in a mass ratio of 5-8:3-8; the matrix resin comprises unsaturated polyester resin, polystyrene particles, butadiene-styrene copolymer particles and styrene; the unsaturated polyester resin is a full maleic anhydride type unsaturated polyester resin; the additives comprise a curing agent, an internal release agent, a phase separation preventing agent, a viscosity reducer and an inorganic color powder.

2. The molding compound for door and window decorative strips according to claim 1, characterized in that: The mass ratio of the maleic anhydride type unsaturated polyester resin, polystyrene particles, butadiene-styrene copolymer particles and styrene is 65-70:13-20:12:10; the molecular weight of the polystyrene particles is 300,000-400,000, and the particle size is 0.3-0.5 mm; the molecular weight of the butadiene-styrene copolymer is 200,000-300,000, and the particle size is 0.3-0.5 mm.

3. The molding compound for door and window decorative strips according to claim 2, characterized in that: The amount of the inhibitor is 14-16% of the mass of the unsaturated polyester resin of the full maleic anhydride type; the amount of the styrene is 40%-60% of the mass of the unsaturated polyester resin.

4. The molding compound for door and window decorative strips according to claim 3, characterized in that: The polymerization inhibitor is one or more of hydroquinone, methyl hydroquinone, and p-tert-butyl catechol.

5. The molding compound for door and window decorative strips according to claim 1, characterized in that: The particle size of the aluminum oxide powder is 1-10 μm; the particle size of the barium sulfate powder is 1-10 μm.

6. The molding compound for door and window decorative strips according to claim 1, characterized in that: The filler is a mixture of one or more of calcium carbonate, aluminum hydroxide and talcum powder, and the filler particle size is 1-5 μm.

7. The molding compound for door and window decorative strips according to claim 1, characterized in that: The reinforcing fibers are chopped glass fibers with a length of 3 to 12 mm.

8. The molding compound for door and window decorative strips according to claim 1, characterized in that: The mass ratio of the curing agent, the internal mold release agent, the phase separation prevention agent, the viscosity reducer and the inorganic color powder is 1-5:0.5-2:0.1-1:0.5-5:0.1-5; the curing agent is one or a mixture of tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, 1,6-di-tert-butyl peroxycarbonyloxyhexane, 2,5-dimethyl-2,5-di(2-ethylhexanoyl peroxide)hexane, 1,1-di-(tert-butyl peroxide)-3,3,5-trimethylcyclohexane, and diisopropylbenzene peroxide; the internal mold release agent is a mixture of polydimethylsiloxane and polyphosphate in a mass ratio of 1-6:1; the phase separation prevention agent is one or a mixture of 1-methyl ether-2-propanol acetate and 1-methyl ether-1-propanol acetate; the viscosity reducer is polyphosphate; and the inorganic color powder is an environmentally friendly inorganic color powder.

9. A method for preparing a molding compound for door and window decorative strips as claimed in claim 1, characterized in that: The specific steps include: S1. The base resin and additives are added to the mixing kettle in order according to the ratio, stirred at 500-1500 rpm for 5-8 min, and then transferred to a double-wrist kneader, and alumina powder and barium sulfate powder are added. The alumina and barium sulfate powders are evenly dispersed in the base resin by the differential rotation of the two stirring paddles in the kneader. The active paddle speed is 20-30 rpm, the active paddle and the driven paddle speed ratio is 1.5-2:1, and the stirring time is 5-8 min to obtain a resin paste; S2. The filler is put into the kneading machine, the kneading machine is turned on to knead the filler and the resin paste, the active paddle speed is 20~30rpm, the active paddle and the driven paddle speed ratio is 1.5~2:1, the stirring time is 20~30min, the stirring is uniform, and then the reinforcing fiber is added to continue kneading and dispersing, the active paddle speed is 20~30rpm, the active paddle and the driven paddle speed ratio is 1.5~2:1, the stirring time is 4~8min, and the molding compound is obtained; S3. After the finished molding material is taken out, it is placed in a tooling of a specified shape for compaction, the air trapped in the material is discharged, and the material is sealed and packaged to obtain a molding material for door and window decorative strips.

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