阅读说明：本技术 低分子量聚氯乙烯、制备方法及护套料、制备方法 (Low molecular weight polyvinyl chloride, preparation method thereof, sheath material and preparation method thereof ) 是由 陈雄 沈斌 于 2020-12-14 设计创作，主要内容包括：本发明公开了一种低分子量聚氯乙烯、制备方法及护套料、制备方法,属于高分子材料技术领域。其低分子量聚氯乙烯的制备方法包括：取聚氯乙烯树脂与四氢呋喃混合形成A混合液,取铝粉和四氯化碳混合形成B混合液；将A混合液与B混合液混合反应后得到低分子量聚氯乙烯。本发明制备的低分子量聚氯乙烯能够参与制备90℃聚氯乙烯护套料,有利于拓宽SG3型聚氯乙烯树脂的分子量分布,改善SG3型聚氯乙烯的加工性能,节约90℃聚氯乙烯护套制备的能耗。(The invention discloses low molecular weight polyvinyl chloride, a preparation method thereof, a sheathing compound and a preparation method thereof, and belongs to the technical field of high polymer materials. The preparation method of the low molecular weight polyvinyl chloride comprises the following steps: mixing polyvinyl chloride resin and tetrahydrofuran to form a mixed solution A, and mixing aluminum powder and carbon tetrachloride to form a mixed solution B; and mixing the mixed solution A and the mixed solution B for reaction to obtain the low molecular weight polyvinyl chloride. The low molecular weight polyvinyl chloride prepared by the invention can participate in the preparation of the 90 ℃ polyvinyl chloride sheath material, is beneficial to widening the molecular weight distribution of SG3 type polyvinyl chloride resin, improving the processability of SG3 type polyvinyl chloride and saving the energy consumption for preparing the 90 ℃ polyvinyl chloride sheath.)

1. The preparation method of the low molecular weight polyvinyl chloride is characterized by comprising the following steps: the method comprises the following steps:

s1, mixing polyvinyl chloride resin powder with tetrahydrofuran, stirring and heating to 58-62 ℃ to form a mixed solution A; mixing and stirring aluminum powder and carbon tetrachloride to form a mixed solution B;

and S2, adding the mixed solution B into the mixed solution A, keeping the mass ratio of the polyvinyl chloride resin powder to the aluminum powder in the mixed solution at 58-62 ℃, stirring for 58-62 min, filtering, collecting filtrate, removing the solvent, and drying to obtain the low molecular weight polyvinyl chloride.

2. The method for preparing low molecular weight polyvinyl chloride according to claim 1, wherein: and in the S1, 38-42 parts by weight of polyvinyl chloride resin powder, 95-105 parts by weight of tetrahydrofuran, 1 part by weight of aluminum powder and 18-22 parts by weight of carbon tetrachloride are taken.

3. The method for preparing low molecular weight polyvinyl chloride according to claim 1, wherein: the solvent removal is carried out by reduced pressure rotary evaporation at 28-32 ℃.

4. The method for preparing low molecular weight polyvinyl chloride according to claim 1, wherein: the drying is carried out for 1.8-2.2 h at the temperature of 75-85 ℃.

5. The low molecular weight polyvinyl chloride produced by the method of claim 1.

6. Low molecular weight polyvinyl chloride according to claim 5, characterized in that: the number average molecular weight of the low molecular weight polyvinyl chloride is 2800-3700.

7. Low molecular weight polyvinyl chloride according to claim 5, characterized in that: the molecular weight distribution of the low molecular weight polyvinyl chloride is 6.2-6.4.

8. Use of a low molecular weight polyvinyl chloride according to any of claims 5 to 7 on a sheathing compound.

9. Sheath material, its characterized in that: the feed is prepared from the following raw materials in parts by weight: 100 parts of SG3 resin powder, 2-5 parts of low molecular weight polyvinyl chloride as described in claim 5, 48-50 parts of dioctyl terephthalate, 40-44 parts of calcium carbonate, 5-8 parts of stabilizer, 2-4 parts of antimony trioxide, 2-4 parts of zinc borate, 0.2-0.4 part of antioxidant, 0.4-0.6 part of calcium stearate and 0.2-0.4 part of polyethylene wax.

10. The preparation method of the sheathing compound according to claim 9, wherein: the method comprises the following steps: weighing SG3 resin powder, low molecular weight polyvinyl chloride and dioctyl terephthalate according to parts by weight, kneading until dispersion is achieved, the kneading temperature is 80-90 ℃, then adding the rest raw materials, stirring and kneading until the material temperature reaches 140-150 ℃, and extruding, granulating and cooling the kneaded materials to obtain the sheath material.

Technical Field

The invention relates to low molecular weight polyvinyl chloride, a preparation method thereof, a sheathing compound and a preparation method thereof, belonging to the technical field of high polymer materials.

Background

Polyvinyl chloride is a polymer obtained by polymerizing vinyl chloride, has a molecular weight in the range of 5 to 11 ten thousand, is a general-purpose plastic having the highest worldwide production, and is widely used in the fields of building materials, industrial products, daily necessities, floor leathers, floor tiles, artificial leathers, pipes, electric wires and cables, packaging films, bottles, foamed materials, sealing materials, fibers, and the like. According to the relevant national standards, the polyvinyl chloride plastics used in the wires and cables are usually 70 ℃ polyvinyl chloride and 90 ℃ polyvinyl chloride.

At present, SG3 type resin powder is generally adopted as a raw material of a 90 ℃ polyvinyl chloride sheathing material, and the SG3 type resin powder has a large molecular weight, so that the polyvinyl chloride sheathing material is difficult to plasticize completely in the processing process, and the appearance of a final product is easily influenced. Meanwhile, when 90 ℃ polyvinyl chloride sheath material particles prepared by SG3 type are used for extruding wires, higher wire extrusion temperature is needed, so that a large amount of energy waste is caused, higher requirements are provided for a stabilizer required by polyvinyl chloride production, and the stabilizer is required to have higher temperature resistance level and more addition amount. In the prior art, in order to improve the processability of polyvinyl chloride, materials with relatively low molecular weight are selected and adopted as raw materials, but the physical properties of products prepared in the way are also poor, and the processed sheath material products are seriously influenced.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides low molecular weight polyvinyl chloride which can be matched with SG3 type polyvinyl chloride to improve the processing performance of the polyvinyl chloride, a preparation method of the polyvinyl chloride, application of the polyvinyl chloride in a sheathing material, a corresponding sheathing material and a preparation method of the polyvinyl chloride.

The purpose of the invention is realized by the following technical scheme: a preparation method of low molecular weight polyvinyl chloride comprises the following steps:

s1, mixing polyvinyl chloride resin powder with tetrahydrofuran, stirring and heating to 58-62 ℃ to form a mixed solution A; taking aluminum powder and carbon tetrachloride, mixing and stirring to form a mixed solution B.

And S2, adding the mixed solution B into the mixed solution A, keeping the mass ratio of the polyvinyl chloride resin powder to the aluminum powder in the mixed solution at 58-62 ℃, stirring for 58-62 min, filtering, collecting filtrate, removing the solvent, and drying to obtain the low molecular weight polyvinyl chloride.

Further, in the step S1, 38 to 42 parts by weight of polyvinyl chloride resin powder, 95 to 105 parts by weight of tetrahydrofuran, 1 part by weight of aluminum powder and 18 to 22 parts by weight of carbon tetrachloride are taken.

Further, the solvent removal is carried out by reduced pressure rotary evaporation at 28-32 ℃.

Further, the drying is carried out for 1.8-2.2 h at the temperature of 75-85 ℃.

The invention also provides the low molecular weight polyvinyl chloride prepared by the preparation method.

Further, the number average molecular weight of the low molecular weight polyvinyl chloride is 2800-3700.

Further, the molecular weight distribution of the low molecular weight polyvinyl chloride is 6.2-6.4.

The invention further provides an application of the low molecular weight polyvinyl chloride prepared by the preparation method in a sheathing material.

The invention also aims to provide a sheath material which is prepared from the following raw materials in parts by weight: 100 parts of SG3 resin powder, 2-5 parts of the prepared low molecular weight polyvinyl chloride, 48-50 parts of dioctyl terephthalate, 40-44 parts of calcium carbonate, 5-8 parts of a stabilizer, 2-4 parts of antimony trioxide, 2-4 parts of zinc borate, 0.2-0.4 part of an antioxidant, 0.4-0.6 part of calcium stearate and 0.2-0.4 part of PE wax.

The invention also provides a preparation method of the sheath material, which comprises the following steps: weighing SG3 resin powder, low molecular weight polyvinyl chloride and dioctyl terephthalate according to parts by weight, kneading until dispersion is achieved, the kneading temperature is 80-90 ℃, then adding the rest raw materials, stirring and kneading until the material temperature reaches 140-150 ℃, and extruding, granulating and cooling the kneaded materials to obtain the sheath material.

The invention has the beneficial effects that:

the preparation method of the low molecular weight polyvinyl chloride adopted by the invention is simple and rapid, and is convenient for rapidly purifying the product, and the low molecular weight polyvinyl chloride prepared by the reaction has lower molecular weight and wider molecular weight distribution. When the low molecular weight polyvinyl chloride prepared by the invention is used for preparing the sheathing material, the molecular weight distribution of SG3 type polyvinyl chloride resin powder is favorably broadened, the physical properties of the blended material are not changed, the processability of SG3 resin powder is obviously improved, the plasticization is easier, the temperature required by the produced sheathing material during wire extrusion is lower, the electric energy loss in production is saved, and the prepared cable has a better surface.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.

The invention provides a preparation method of low molecular weight polyvinyl chloride, which comprises the following steps:

s1, mixing polyvinyl chloride resin powder with tetrahydrofuran, stirring and heating to 58-62 ℃ to form a mixed solution A; taking aluminum powder and carbon tetrachloride, mixing and stirring to form a mixed solution B.

And S2, adding the mixed solution B into the mixed solution A, keeping the mass ratio of the polyvinyl chloride resin powder to the aluminum powder in the mixed solution at 58-62 ℃ for stirring for 58-62 min, filtering, collecting filtrate, removing the solvent, and drying to obtain the low molecular weight polyvinyl chloride.

The polyvinyl chloride resin powder adopted in the process of preparing the low molecular weight polyvinyl chloride is prepared by a calcium carbide method, the molecular weight of the polyvinyl chloride resin powder is in the range of forty thousand to eleven thousand, and the molecular weight distribution is about 2. And mixing and reacting a mixed solution formed by polyvinyl chloride and tetrahydrofuran with a mixed solution formed by aluminum powder and carbon tetrachloride to prepare the polyvinyl chloride with low molecular weight and wider molecular weight distribution. Wherein, in S1, 38-42 parts by weight of polyvinyl chloride resin powder, 95-105 parts by weight of tetrahydrofuran, 1 part by weight of aluminum powder and 18-22 parts by weight of carbon tetrachloride are taken. And removing the solvent in the filtrate in the S2 is realized by placing the filtrate at 28-32 ℃ and performing reduced pressure rotary evaporation, and the drying process of the solid product after the solvent is removed is performed at 75-85 ℃ and is performed for 1.8-2.2 h.

The invention also provides the low molecular weight polyvinyl chloride prepared by the preparation method, wherein the number average molecular weight of the low molecular weight polyvinyl chloride is 2800-3700, and the molecular weight distribution is 6.2-6.4.

The invention further provides an application of the low molecular weight polyvinyl chloride prepared by the preparation method in a sheathing material.

Specifically, when the low molecular weight polyvinyl chloride prepared by the preparation method is applied to a sheathing material, the sheathing material is prepared from the following raw materials in parts by weight: 100 parts of SG3 resin powder, 2-5 parts of the prepared low molecular weight polyvinyl chloride, 48-50 parts of dioctyl terephthalate, 40-44 parts of calcium carbonate, 5-8 parts of a stabilizer, 2-4 parts of antimony trioxide, 2-4 parts of zinc borate, 0.2-0.4 part of an antioxidant, 0.4-0.6 part of calcium stearate and 0.2-0.4 part of polyethylene wax. In the above raw materials, the stabilizer can adopt one or more of lead salt, metal soap or rare earth stabilizer, such as tribasic lead sulfate, dibasic lead stearate, calcium/zinc composite stabilizer, barium/zinc composite stabilizer, etc.; the antioxidant can be antioxidant CA, antioxidant TPP, antioxidant 1076, etc. Antimony trioxide is used as a flame retardant in combination with zinc borate, and calcium stearate is used as a lubricant in combination with PE wax.

The preparation method of the sheath material comprises the following steps: weighing SG3 resin powder, low molecular weight polyvinyl chloride and dioctyl terephthalate according to parts by weight, kneading until dispersion is achieved, the kneading temperature is 80-90 ℃, then adding the rest raw materials, stirring and kneading until the material temperature reaches 140-150 ℃, and extruding, granulating and cooling the kneaded materials to obtain the sheath material.

Example one

The embodiment provides a preparation method of low molecular weight polyvinyl chloride and the prepared polyvinyl chloride, and the preparation method comprises the following steps:

s1, weighing 38kg of polyvinyl chloride resin powder and 95kg of tetrahydrofuran, mixing, stirring and heating to 62 ℃ to form a mixed solution A; 1kg of aluminum powder and 18kg of carbon tetrachloride are mixed and stirred to form a mixed solution B.

S2, adding the mixed solution B into the mixed solution A, keeping the mixed solution at the temperature of 61 +/-1 ℃, stirring for 58min, filtering, collecting the filtrate, evaporating and removing the solvent in the filtrate by using a rotary evaporator, drying for 1.8h at the temperature of 85 ℃ after the water bath temperature in the rotary evaporation process is 31 +/-1 ℃, and drying to obtain the low molecular weight polyvinyl chloride, wherein the number average molecular weight of the low molecular weight polyvinyl chloride prepared in the embodiment is 3.16 multiplied by 10³The molecular weight distribution was 6.3.

Example two

The difference between the present embodiment and the first embodiment is mainly as follows: in S1 of this example, 42kg of the polyvinyl chloride resin powder and 105kg of the tetrahydrofuran were weighed, and the two were mixed, stirred and heated to 58 ℃ to form a mixed solution a. Weighing 1kg of aluminum powder and 22 parts of carbon tetrachloride, and mixing to form a mixed solution B. In S2, the mixed solution a and the mixed solution B are mixed, stirred for 62min at 59 ± 1 ℃ and filtered, the filtrate is rotary evaporated at 29 ± 1 ℃ in a water bath, then dried for 2.2h at 75 ℃ and dried to obtain the low molecular weight polyvinyl chloride, the number average molecular weight of the low molecular weight polyvinyl chloride prepared in this example is 3.67 × 10³The molecular weight distribution was 6.4.

EXAMPLE III

The difference between the present embodiment and the first embodiment is mainly as follows: in S1 of this example, 40kg of the polyvinyl chloride resin powder and 100kg of the tetrahydrofuran were weighed, and the two were mixed, stirred and heated to 60 ℃ to form a mixed solution a. Weighing 1kg of aluminum powder and 20 parts of carbon tetrachloride, and mixing to form a mixed solution B. And S2, mixing the mixed solution A and the mixed solution B, keeping the mixed solution at the temperature of 60 +/-1 ℃, stirring for 60min, filtering, carrying out rotary evaporation on the filtrate at the water bath temperature of 30 +/-1 ℃, drying for 2h at the temperature of 80 ℃, and drying to obtain the low molecular weight polyvinyl chlorideThe low molecular weight polyvinyl chloride prepared in examples had a number average molecular weight of 2.83X 10³The molecular weight distribution was 6.4.

Example four

The embodiment provides application of low molecular weight polyvinyl chloride to a sheathing material, in particular to a sheathing material and a preparation method thereof, wherein the preparation method comprises the following steps: 100kg of SG3 resin powder, 3kg of low molecular weight polyvinyl chloride and 48kg of dioctyl terephthalate are weighed and kneaded at 85 ℃ by a high-speed mixer until the materials are dispersed, then 42kg of calcium carbonate, 5kg of stabilizing agent, 2kg of antimony trioxide, 2kg of zinc borate, 0.2kg of antioxidant, 0.4kg of calcium stearate and 0.2kg of polyethylene wax are added, the materials are rapidly stirred and kneaded until the material temperature reaches 145 ℃. In this example, the low molecular weight polyvinyl chloride was used as the product prepared in the first example, and the stabilizer was an XT-1 type rare earth stabilizer, and the antioxidant was antioxidant CA. And (2) mixing and extruding the kneaded material through an SDJ75-180 double-stage mixing extruder, setting the temperature of a double-screw temperature control zone of the extruder to be 120 ℃, 130 ℃, 120 ℃, 110 ℃, 105 ℃ and 80 ℃, setting the temperature of three single-screw temperature control zones to be 85 ℃, 110 ℃ and 120 ℃, setting the temperature of a die head to be 150 ℃, setting the current of a double screw to be 130A, setting the feeding frequency to be 35Hz, setting the frequency of the double screw to be 40Hz, setting the frequency of the single screw to be 35Hz, cutting the extruded material into granules, preparing square granules of 4mm multiplied by 3mm or cylindrical granules of a certain size, and cooling the granules to obtain the.

EXAMPLE five

The present embodiment is different from the fourth embodiment mainly in that: 100kg of SG3 resin powder, 5kg of low molecular weight polyvinyl chloride and 50kg of dioctyl terephthalate are weighed and kneaded to be dispersed at the temperature of 80 ℃, then 44kg of calcium carbonate, 8kg of barium-cadmium composite stabilizer, 4kg of antimony trioxide, 4kg of zinc borate, 0.4kg of antioxidant 1076, 0.6kg of calcium stearate and 0.4kg of polyethylene wax are added, and the materials are rapidly stirred and kneaded until the material temperature reaches 140 ℃. The low molecular weight polyvinyl chloride of this example was the product prepared in example two, and the rest was the same as in example four.

EXAMPLE six

The present embodiment is different from the fourth embodiment mainly in that: 100kg of SG3 resin powder, 2kg of low molecular weight polyvinyl chloride and 49kg of dioctyl terephthalate are weighed and kneaded to be dispersed at 90 ℃, then 40kg of calcium carbonate, 6kg of barium-cadmium composite stabilizer, 3kg of antimony trioxide, 3kg of zinc borate, 0.3kg of antioxidant CA, 0.5kg of calcium stearate and 0.3kg of polyethylene wax are added, and the mixture is rapidly stirred and kneaded until the material temperature reaches 150 ℃. The low molecular weight polyvinyl chloride of this example was the product prepared in example three, and the rest was the same as example four.

EXAMPLE seven

The present embodiment is different from the fourth embodiment mainly in that: 100kg of SG3 resin powder, 4kg of low molecular weight polyvinyl chloride and 48kg of dioctyl terephthalate are weighed and kneaded to be dispersed at 88 ℃, then 43kg of calcium carbonate, 7kg of XT-1 type rare earth stabilizer, 3kg of antimony trioxide, 3kg of zinc borate, 0.3kg of antioxidant 1076, 0.5kg of calcium stearate and 0.3kg of polyethylene wax are added, and the mixture is rapidly stirred and kneaded until the material temperature reaches 148 ℃. The low molecular weight polyvinyl chloride of this example was the product prepared in example three, and the rest was the same as example four.

Comparative example

The comparative example provides a sheathing compound without adding low molecular weight polyvinyl chloride, weighing 100kg of SG3 resin powder, 50kg of dioctyl terephthalate, 8kg of calcium-zinc composite stabilizer, 35kg of heavy calcium carbonate, 0.3kg of antioxidant, 3kg of antimony trioxide, 3kg of zinc borate, 0.5kg of calcium stearate and 0.3kg of polyethylene wax, mixing for 5min in a high-speed mixer, and performing extrusion granulation by using a double-screw extruder at the extrusion temperature of 175 ℃ to prepare the sheathing compound.

Product detection

The jacket materials prepared in the fourth to seventh examples and the comparative example were tested according to methods of GB/T2951.11-2008 and GB/T2951.12-2008, and the mechanical properties of the jacket materials were tested, and the test results are shown in Table 1.

Table 1 results of performance test of sheath materials prepared in examples four to seven

Test item	Example four	EXAMPLE five	EXAMPLE six	EXAMPLE seven	Comparative example
						Tensile strength/MPa	18.6	18.4	19.2	19.5	18.5
Elongation at break/%	280	273	324	316	290
						Thermal deformation/%)	30	31	28	26	29
Heat stability at 200 deg.CTiming/min	100	100	100	100	100
						Volume resistivity at 20 degree/(omega. m)	8×1010	7.8×1010	8.3×1010	8.5×1010	8.2×1010
Tensile Strength/MPa after aging	18	17.9	18.8	19.2	18
						Elongation at break after aging/%)	276	268	317	309	285
Heat aged mass loss/(g/m)2)	8.5	9.4	8.6	8.3	8.7

As can be seen from Table 1, the physical properties of the sheath material prepared by adding the low molecular weight polyvinyl chloride prepared by the invention to the sheath material in proportion are similar to those of the sheath material of the comparative example, i.e. the physical properties of the sheath material are not affected by the addition of the low molecular weight polyvinyl chloride. The low molecular weight polyvinyl chloride prepared by the invention is matched with SG3 type polyvinyl chloride resin powder, so that the molecular weight distribution of the SG3 type polyvinyl chloride resin powder is widened, the processing performance of the polyvinyl chloride resin powder is improved, the polyvinyl chloride resin powder is still good and stable in physical performance, the SG3 type polyvinyl chloride resin is easy to plasticize, the temperature of a sheath material during extrusion is reduced, the electric energy loss in production is reduced, and the prepared sheath material is good in plasticization, uniform in color and no obvious impurity.

The foregoing is illustrative of the preferred embodiments of this invention, and it is to be understood that the invention is not limited to the precise form disclosed herein and that various other combinations, modifications, and environments may be resorted to, falling within the scope of the concept as disclosed herein, either as described above or as apparent to those skilled in the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.