Filable rotational molding composite material and preparation method thereof

Abstract

The invention provides a fillable rotational molding composite material and a preparation method thereof, and belongs to the field of rotational molding. The fillable rotational molding composite material is composed of 30%-90% of A material powder and 10%-70% of B material oligomer, and the A material powder comprises 90%-99.9% of matrix resin and 0.1%-10% of auxiliaries. The powder and the oligomer are mixed to obtain a solid composite material which can be molded at normal temperature, the composite material is fixed in a corresponding cavity of a mold, a rotational molding material is normally put into the mold for rotational molding, and the problems of material shortage, material leakage and even non-molding of a complex and narrow cavity are solved.

Description

Technical Field

[0001] The invention relates to a fillable rotationally molded composite material and a preparation method thereof, and belongs to the field of rotational molding. Background Art

[0002] Rotomolding is also known as rotational molding, rotational molding, rotational modeling, rotational molding, etc. The rotational molding process is to first add the plastic raw material into the mold, and then the mold is continuously rotated along two vertical axes and heated, so that the plastic raw material in the mold is gradually and evenly coated, melted and adhered to the entire surface of the mold cavity under the action of gravity and heat energy, and formed into the required shape, and then cooled and molded, and finally the product is obtained.

[0003] The patent with application number 202110553362.3 provides a large-particle rotomolding composite material and its preparation method and application. The mixture of powder and large particles is rotomolded, and the powder material is preferentially attached to the mold, eliminating the phenomenon of material shortage and leakage. The large particles are attached to the powder coating, and the powder also fills the gaps between the large particles, improving the mechanical properties of the rotomolded products. However, during the rotomolding process, it is often encountered that the rotomolding powder is difficult to flow to the position due to the complex and narrow cavity in some areas of the mold, resulting in the rotomolding product being short of material or even unformed at this position. This problem is difficult to solve by improving the fluidity of the powder, applying a flow aid, and changing the rotomolding process, which causes great trouble to rotomolding production. Therefore, it is of great significance to provide a fillable rotomolding composite material and a preparation method. Summary of the invention

[0004] In order to solve the problem that products in narrow mold cavities are difficult to form during rotational molding, the present invention provides a fillable rotational molding composite material on the one hand, and a method for preparing a fillable rotational molding composite material on the other hand. Powder and oligomers are mixed under certain conditions to obtain a solid composite material that can be molded at room temperature. The composite material is fixed to the corresponding cavity of the mold, and rotational molding material is normally put into the mold for rotational molding, thereby solving the problems of lack of material, leakage of material and even non-molding in complex and narrow cavities.

[0005] In order to achieve the above object, the present invention provides the following technical solutions: A fillable rotational molding composite material comprises, by mass percentage, 30% to 90% of A material powder and 10% to 70% of B material oligomer, wherein the ratio of A material powder to B material oligomer is 1:1-3:1.

[0006] Preferably, the material A powder comprises: base resin: 90% to 99.9%, auxiliary agent: 0.1% to 10%.

[0007] Preferably, the matrix resin in the A material powder is selected from polyethylene, polypropylene, nylon, polycarbonate, polylactic acid, elastomeric materials, or derivatives of the above materials, or modified materials of the above materials with flame retardant, foaming, weather-resistant, cross-linking, and dyeing functions.

[0008] Preferably, the powder flowability of the material A powder is ≤35s / 100g, and the particle size distribution D95 is ≤650μm.

[0009] Preferably, the B material oligomer is hydrogenated petroleum resin, hydrogenated rosin, paraffin, soybean wax, vaseline, or a combination of the above materials.

[0010] Preferably, the auxiliary agent is at least one of antioxidant 1078, antioxidant 168, antioxidant 1098, antioxidant 686, antioxidant 1010, antioxidant 300, antioxidant 1790, antioxidant 626, UV400, UV928, UV326, UV329, ethylene bisstearamide, silicone powder zinc stearate, and barium stearate.

[0011] Preferably, the fillable rotationally molded composite material comprises the following components: A material powder 60%: polyethylene 98.35%, additives 1.65%; B material oligomer 40%: paraffin and vaseline; The ratio of paraffin wax and vaseline is 1:1.

[0012] The present invention also provides another technical solution: A method for preparing a fillable rotationally molded composite material comprises the following steps: S1: Prepare material A powder; S2: Coat material A and material B in a coating machine at a ratio of 1:1-3:1.

[0013] Preferably, the preparation method of the A material powder is as follows: the base resin and the auxiliary agent in the A material are mixed for 3 to 20 minutes, the temperature of each section of the extruder is set to 100 to 280° C., the screw speed is 80 to 500 rpm, and a twin-screw extruder is used for melt blending and granulation, and dried to obtain the A material particles; the A material particles are mechanically ground to obtain the A material powder.

[0014] Preferably, in the grinding process, the grinding disc temperature is ≤75°C and the grinding disc rotation speed is 2000-3500rpm.

[0015] Preferably, in the coating process, the rotation speed is 2-1000 rpm, the heating temperature is 20-65° C., and the coating time is 20-45 min.

[0016] Therefore, the present invention has the following benefits: (1) The rotomolding material of the present invention is mixed with powder and oligomer to obtain a solid composite material that can be shaped at room temperature. The composite material is fixed to the corresponding cavity of the mold, and the rotomolding material is normally put into the mold for rotomolding, thereby solving the problem that the product is difficult to form in the narrow cavity of the mold during the rotomolding process. (2) The preparation method of the material of the present invention is simple, does not require complex equipment, is low in cost, and is easy to realize industrial operation. DETAILED DESCRIPTION

[0017] Example 1 A fillable rotational molding composite material comprises, by mass percentage, 60% of material A powder: 98.35% of polyethylene (LL9450U, PTT) and 1.65% of an auxiliary agent; 40% of material B oligomer: a paraffin wax and vaseline compound, wherein the ratio of the paraffin wax to the vaseline is 1:1; and the auxiliary agents are antioxidant 1098, antioxidant 686, UV928 and silicone powder.

[0018] A method for preparing a fillable rotationally molded composite material comprises the following steps: S1: Preparation of material A powder: polyethylene (LL9450U, PTT), antioxidant 1098, antioxidant 686, UV928, silicone powder are mixed in a mass ratio of 98.35:0.40:1.00:0.05:0.20, mixed for 15 min at 100 rpm using a high-speed mixer, the temperature of each section of the extruder is set to 100-230°C, the screw speed is 480 rpm, and the twin-screw extruder is used for melt blending and drying to obtain material A particles; the material A powder is ground at a grinding disc speed of 3000 rpm and a grinding disc temperature of <65°C, and the material A powder is a black powder with a particle size D95≤500μm and a powder flowability of 30s / 100g; S2: Coating: The powder of material A and the compound of material B oligomer paraffin and vaseline were mixed in a mass ratio of 60:40, and coated in a coating machine. The coating process parameters were: temperature 40°C, rotation speed 75rpm, coating time 80min, to obtain a fillable rotational molding composite material; S3: Rolling: Fix the fillable rotomolding composite material at the corresponding position in the rotomolding cavity, put the rotomolding powder produced normally into the mold, and perform rotomolding.

[0019] Example 2 A fillable rotational molding composite material comprises, by mass percentage, 50% of material A powder: 98.84% of polyethylene and 1.16% of an auxiliary agent; 50% of material B oligomer: a compound of hydrogenated petroleum resin and soybean wax, wherein the ratio of hydrogenated petroleum resin to soybean wax is 3:2; and the auxiliary agents are antioxidant 1010, antioxidant 300, UV329 and barium stearate.

[0020] A method for preparing a fillable rotationally molded composite material comprises the following steps: S1: Preparation of material A powder: polyethylene (UR654, Lotte Chemical), antioxidant 1010, antioxidant 300, UV329, and barium stearate were mixed in a mass ratio of 98.84:0.20:0.50:0.06:0.40, mixed in a high-speed mixer at 120 rpm for 8 min, the temperature of each section of the extruder was set to 100-220°C, the screw speed was 420 rpm, and the twin-screw extruder was used for melt blending and drying to obtain material A particles; the material A powder was ground at a grinding disc speed of 2700 rpm and a grinding disc temperature of <65°C, and the material A powder was a black powder with a particle size D95≤530μm and a powder flowability of 26s / 100g; S2: Coating: The powder of material A and the oligomer paraffin and soybean wax of material B were mixed in a mass ratio of 50:50, and coated in a coating machine. The coating process parameters were: temperature 40°C, rotation speed 75rpm, coating time 80min, to obtain a fillable rotational molding composite material; S3: Rolling: Fix the fillable rotomolding composite material at the corresponding position in the rotomolding cavity, put the rotomolding powder produced normally into the mold, and perform rotomolding.

[0021] Example 3 A fillable rotational molding composite material comprises, by mass percentage, 60% of A material powder: 98.96% of polyethylene (DMDA-8008, Fujian United), 1.04% of auxiliary agent; 40% of B material oligomer: paraffin; the auxiliary agents are antioxidant 1078, antioxidant 168, UV400, and zinc stearate.

[0022] A method for preparing a fillable rotationally molded composite material comprises the following steps: S1: Preparation of material A powder: (DMDA-8008, Fujian United), antioxidant 1078, antioxidant 168, UV400, zinc stearate are mixed in a mass ratio of 98.96:0.20:0.50:0.04:0.30, mixed in a high-speed mixer at 80 rpm for 10 min, the temperature of each section of the extruder is set to 100-230°C, the screw speed is 450 rpm, and the twin-screw extruder is used for melt blending and drying to obtain material A particles; the material A powder is ground at a grinding disc speed of 2800 rpm and a grinding disc temperature of ≤75°C. The material A powder is a black powder with a particle size D95≤555μm and a powder flowability of 33s / 100g; S2: Coating: The powder of material A and the oligomer paraffin of material B were mixed in a mass ratio of 60:40, and coated in a coating machine. The coating process parameters were: temperature 35°C, rotation speed 55 rpm, coating time 35 min, to obtain a fillable rotational molding composite material; S3: Rolling: Fix the fillable rotomolding composite material at the corresponding position in the rotomolding cavity, put the rotomolding powder produced normally into the mold, and perform rotomolding.

[0023] Example 4 A fillable rotational molding composite material comprises, by mass percentage, 60% of A material powder: 98.35% of polyethylene (LL9450U, PTT), 1.65% of auxiliary agent; 40% of B material oligomer: hydrogenated petroleum resin; the auxiliary agents are antioxidant 1098, antioxidant 686, UV928, and silicone powder.

[0024] A method for preparing a fillable rotationally molded composite material comprises the following steps: S1: Polyethylene (LL9450U, PTT), antioxidant 1098, antioxidant 686, UV928, silicone powder are mixed in a mass ratio of 98.35:0.40:1.00:0.05:0.20, mixed in a high-speed mixer at 100 rpm for 15 min, the temperature of each section of the extruder is set to 100-230°C, the screw speed is 480 rpm, and the twin-screw extruder is used for melt blending and drying to obtain A material particles; the powder is ground at a grinding disc speed of 3000 rpm and a grinding disc temperature of <65°C. The A material powder is a black powder with a particle size D95≤500μm and a powder flowability of 30s / 100g; S2: Coating: Mix the powder of material A and the oligomer hydrogenated petroleum resin of material B at a mass ratio of 50:50, and coat them in a coating machine. The coating process parameters are: temperature 37°C, rotation speed 80rpm, coating time 55min, to obtain a fillable rotational molding composite material; S3: Rolling: Fix the fillable rotomolding composite material at the corresponding position in the rotomolding cavity, put the rotomolding powder produced normally into the mold, and perform rotomolding.

[0025] Example 5 A fillable rotational molding composite material comprises, by mass percentage, 60% of A material powder: 98.84% of polyethylene (UR654, Lotte Chemical), 1.16% of auxiliary agent; 40% of B material oligomer: soybean wax; the auxiliary agents are antioxidant 1010, antioxidant 300, UV329, and barium stearate.

[0026] A method for preparing a fillable rotationally molded composite material comprises the following steps: S1: Preparation of material A powder: polyethylene (UR654, Lotte Chemical), antioxidant 1010, antioxidant 300, UV329, and barium stearate were mixed in a mass ratio of 98.84:0.20:0.50:0.06:0.40, mixed in a high-speed mixer at 120 rpm for 8 min, the temperature of each section of the extruder was set to 100-220°C, the screw speed was 420 rpm, and the twin-screw extruder was used for melt blending and drying to obtain material A particles; the material A powder was ground at a grinding disc speed of 2700 rpm and a grinding disc temperature of <65°C, and the material A powder was a black powder with a particle size D95≤530μm and a powder flowability of 26s / 100g; S2: Coating: The powder of material A and the oligomer soybean wax of material B were mixed in a mass ratio of 55:45, and coated in a coating machine. The coating process parameters were: temperature 40°C, rotation speed 75rpm, coating time 80min, to obtain a fillable rotational molding composite material; S3: Rolling: Fix the fillable rotomolding composite material at the corresponding position in the rotomolding cavity, put the rotomolding powder produced normally into the mold, and perform rotomolding.

[0027] Example 6 A fillable rotational molding composite material comprises, by mass percentage, 65% of A material powder: 98.58% of polypropylene (10T1, Total), 1.42% of auxiliary agent; 35% of B material oligomer: soybean wax; the auxiliary agents are antioxidant 1790, antioxidant 626, UV326, and ethylene bis stearamide.

[0028] A method for preparing a fillable rotationally molded composite material comprises the following steps: S1: Preparation of material A powder: polypropylene (10T1, Total), antioxidant 1790, antioxidant 626, UV326, and ethylene bisstearamide were mixed in a mass ratio of 98.58:0.30:0.70:0.07:0.35, and mixed for 7 min at 150 rpm using a high-speed mixer. The temperature of each section of the extruder was set at 130-240°C, the screw speed was 380 rpm, and the twin-screw extruder was used for melt blending and drying to obtain material A particles; freeze grinding was performed at a grinding disc speed of 2700 rpm, and the material A powder was a black powder with a particle size D95≤550μm and a powder flowability of 35s / 100g; S2: Coating: Material A powder and material B oligomer soybean wax were mixed in a mass ratio of 65:35, and coated in a coating machine. The coating process parameters were: temperature 45°C, rotation speed 100 rpm, coating time 45 min, to obtain a fillable rotational molding composite material; S3: Rolling: Fix the fillable rotomolding composite material at the corresponding position in the rotomolding cavity, put the rotomolding powder produced normally into the mold, and perform rotomolding.

[0029] Comparative Example 1 Polyethylene (LL9450U, PTT), antioxidant 1098, antioxidant 686, UV928, and silicone powder are mixed in a mass ratio of 98.35:0.40:1.00:0.05:0.20, mixed for 15 minutes at 100 rpm by a high-speed mixer, the temperature of each section of the extruder is set to 100-230°C, the screw speed is 480 rpm, and the twin-screw extruder is used for melt blending and drying to obtain A material particles; the A material powder is ground at a grinding disc speed of 3000 rpm and a grinding disc temperature of less than 65°C, and the A material powder is a black powder with a particle size D95≤500 μm and a powder fluidity of 30 s / 100 g; the obtained powder is put into a rotational molding mold for rotational molding.

[0030] The difference from Example 1 is that this comparative example only uses material A powder for rotational molding.

[0031] Comparative Example 2 A fillable rotational molding composite material comprises, by mass percentage, 80% of material A powder: 98.35% of polyethylene (LL9450U, PTT) and 1.65% of an auxiliary agent; 20% of material B oligomer: a paraffin wax and vaseline compound, wherein the ratio of the paraffin wax to the vaseline is 1:1; and the auxiliary agents are antioxidant 1098, antioxidant 686, UV928 and silicone powder.

[0032] A method for preparing a fillable rotationally molded composite material comprises the following steps: S1: Preparation of material A powder: polyethylene (LL9450U, PTT), antioxidant 1098, antioxidant 686, UV928, silicone powder are mixed in a mass ratio of 98.35:0.40:1.00:0.05:0.20, mixed for 15 min at 100 rpm using a high-speed mixer, the temperature of each section of the extruder is set to 100-230°C, the screw speed is 480 rpm, and the twin-screw extruder is used for melt blending and drying to obtain material A particles; the material A powder is ground at a grinding disc speed of 3000 rpm and a grinding disc temperature of <65°C, and the material A powder is a black powder with a particle size D95≤500μm and a powder flowability of 30s / 100g; S2: Coating: The powder of material A and the compound of material B oligomer paraffin and vaseline were mixed in a mass ratio of 4:1, and coated in a coating machine. The coating process parameters were: temperature 40°C, rotation speed 75rpm, coating time 80min, to obtain a fillable rotational molding composite material; S3: Rolling: Fix the fillable rotomolding composite material at the corresponding position in the rotomolding cavity, put the rotomolding powder produced normally into the mold, and perform rotomolding.

[0033] The specific implementation of this comparative example is the same as that of Example 1, except that the ratio of the A material powder to the B material oligomer is 4:1, and the other conditions are the same as those of Example 1.

[0034] Comparative Example 3 A fillable rotational molding composite material comprises, by mass percentage, 25% of A material powder: 98.96% of polyethylene (DMDA-8008, Fujian United), 1.04% of auxiliary agent; 75% of B material oligomer: paraffin; the auxiliary agents are antioxidant 1078, antioxidant 168, UV400, and zinc stearate.

[0035] A method for preparing a fillable rotationally molded composite material comprises the following steps: S1: Preparation of material A powder: (DMDA-8008, Fujian United), antioxidant 1078, antioxidant 168, UV400, zinc stearate are mixed in a mass ratio of 98.96:0.20:0.50:0.04:0.30, mixed in a high-speed mixer at 80 rpm for 10 min, the temperature of each section of the extruder is set to 100-230°C, the screw speed is 450 rpm, and the twin-screw extruder is used for melt blending and drying to obtain material A particles; the material A powder is ground at a grinding disc speed of 2800 rpm and a grinding disc temperature of ≤75°C. The material A powder is a black powder with a particle size D95≤555μm and a powder flowability of 33s / 100g; S2: Coating: Mix the powder of material A and the oligomer paraffin of material B in a mass ratio of 1:3, and coat them in a coating machine. The coating process parameters are: temperature 35°C, rotation speed 55rpm, coating time 35min, to obtain a fillable rotationally molded composite material; S3: Rolling: Fix the fillable rotationally molded composite material at the corresponding position in the rotationally molded cavity, put the rotationally molded powder in normal production into the mold, and carry out rotational molding.

[0036] The specific implementation of this comparative example is the same as that of Example 3, except that the ratio of the A material powder to the B material oligomer is 1:3, and the other conditions are the same as those of Example 3.

[0037] Performance Testing The results are shown in Table 1.

[0038] Table 1 Performance test results.

[0039] As shown in the performance test results of Table 1, the performance of Examples 1-6 is better than that of the comparative example. Therefore, the roto-molded composite material prepared by the present invention has no material shortage or leakage at the edges during roto-molding in a narrow cavity, and the narrow cavity part of the product is not damaged by being hit with a hammer. Compared with Example 1, Comparative Example 1 only used A material powder for roto-molding, and there were problems of material shortage or leakage at the edges of the narrow cavity and pores on the surface of the product. Because in roto-molding, the cavity in some areas of the mold is complex and narrow, and it is difficult for the roto-molding powder to flow to this position, so that the roto-molded product has material shortage or even unmolded problems at this position. In Comparative Example 2, the ratio of A material powder to B material oligomer is higher than the optimal range of the present invention, and in Comparative Example 3, the ratio of A material powder to B material oligomer is lower than the optimal range of the present invention. The products of Comparative Examples 2 and 3 both have material shortage or leakage at the edges of the narrow cavity. In Comparative Example 2, due to the high content of powder in material A, the narrow cavity of the product will not be damaged by hammering, and the impact resistance is strong, but bubbles will appear on the surface of the product; in Comparative Example 3, due to the high content of oligomer in material B, no bubbles will appear on the surface of the product, but the narrow cavity of the product will be damaged by hammering, and the impact resistance is low. Overall, the performance of Comparative Examples 1-3 is lower than that of Examples 1-6.

[0040] Therefore, the present invention adds the B material oligomer to wrap the A material powder to soften and plasticize it to form the skeleton of the composite material, fix the composite material into the corresponding cavity of the mold, and put the rotational molding material into the mold normally for rotational molding, so as to solve the problems of lack of material, leakage of material and even non-molding in complex and narrow cavities, and there is no pore phenomenon on the surface of the product.

[0041] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A fillable rotationally molded composite material, characterized in that: Calculated by mass percentage, the material A powder comprises 30% to 90% and the material B oligomer 10% to 70%. The ratio of the material A powder to the material B oligomer is 1:1-3:

1.

2. The fillable rotationally molded composite material according to claim 1, characterized in that: The material A powder comprises: base resin: 90% to 99.9% and auxiliary agent: 0.1% to 10%.

3. The fillable rotationally molded composite material according to claim 2, characterized in that: The powder flowability of the material A powder is ≤35s / 100g, the particle size distribution D95 is ≤650μm, and the matrix resin is selected from at least one of polyethylene, polypropylene, nylon, polylactic acid, and polycarbonate.

4. The fillable rotationally molded composite material according to claim 1, characterized in that: The B material oligomer is selected from at least one of hydrogenated petroleum resin, hydrogenated rosin, paraffin, soybean wax and vaseline.

5. The fillable rotationally molded composite material according to claim 1, characterized in that: The auxiliary agent is at least one of antioxidant 1078, antioxidant 168, antioxidant 1098, antioxidant 686, antioxidant 1010, antioxidant 300, antioxidant 1790, antioxidant 626, UV400, UV928, UV326, UV329, ethylene bis stearamide, silicone powder zinc stearate, and barium stearate.

6. The fillable rotationally molded composite material according to any one of claims 1 to 5, characterized in that: Calculated by mass percentage, it includes the following components: A material powder 60%: polyethylene 98.35%, additives 1.65%; B material oligomer 40%: paraffin and vaseline; The ratio of paraffin wax and vaseline is 1:

1.

7. A method for preparing a fillable rotationally molded composite material, characterized in that: The following steps are involved: S1: prepare material A powder; S2: coat material A and material B in a coating machine at a ratio of 1:1-3:

1.

8. The method for preparing a fillable rotationally molded composite material according to claim 7, characterized in that: The preparation method of the material A powder is as follows: the base resin and the auxiliary agent in the material A are mixed for 3 to 20 minutes, the temperature of each section of the extruder is set to 100 to 280° C., the screw speed is 80 to 500 rpm, the twin-screw extruder is used for melt blending and granulation, and the mixture is dried to obtain the material A particles; the material A particles are mechanically ground to obtain the material A powder.

9. The method for preparing a fillable rotationally molded composite material according to claim 8, characterized in that: In the grinding process, the grinding disc temperature is ≤75°C and the grinding disc rotation speed is 2000-3500rpm.

10. The method for preparing a fillable rotationally molded composite material according to claim 7, characterized in that: In the coating process, the rotation speed is 2-1000 rpm, the heating temperature is 20-65° C., and the coating time is 20-45 min.

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