A kind of hard silicone foam and preparation method thereof

Abstract

The present invention relates to the technical field of foaming materials, and discloses a hard silicone foam, including liquid A material and B material; the mass ratio of the A material and the B material is 1:1; the liquid A material includes the following components by weight: 60-100 parts of methyl vinyl siloxane, 5-45 parts of reinforcing agent, and 0.05-3 parts of platinum complex; the liquid B material includes the following components by weight: 0.5-8 parts of hollow microspheres, 0.5-30 parts of hydrogen-containing silicone oil, and 5-25 parts of flame retardant. The present invention also discloses a preparation method of the above-mentioned hard silicone foam: the A material and the B material are mixed and then injected and coated between the upper and lower auxiliary material films, and then calendered and high-temperature foamed and cured to form. The hard silicone foam of the present invention has the advantages of good conformability, small permanent deformation after high-temperature aging, medium hardness and high elasticity, flame retardancy, etc., and can be used for formation, support, module installation buffer protection, etc. in the process of battery cell manufacturing.

Description

Technical Field

[0001] The invention relates to the technical field of foaming materials, in particular to a hard silicone foam and a preparation method thereof. Background Art

[0002] In the formation process or module assembly section of soft-pack lithium batteries, auxiliary material gaskets are required to block, wrap or buffer the battery cells. The traditional solution is to use solid silicone or high-temperature glue foam cotton as auxiliary material gaskets. The materials of these two products are both high-temperature vulcanized silicone systems. Among them, solid silicone is relatively hard, has poor compressibility, and has average conformity to the surface of the battery cell. Therefore, during the formation and pressure application process, there will be virtual connections near the raised areas on the surface of the battery cell, and uneven force will occur, resulting in inconsistent pressure on the materials inside the battery cell, uneven SEI film formed, and poor battery performance. Although high-temperature glue foam cotton solves the problem of surface conformity, its rebound support force is relatively low, the product has poor aging resistance, and large permanent deformation. High-temperature glue foam cotton usually uses azo chemical foaming agents. This type of foaming agent releases a lot of heat when working, which can easily cause local overheating, resulting in excessive or uneven bubbles. Moreover, under high temperature conditions, azo foaming agents are easy to decompose to form residues and cause irreversible collapse of the silicone base material, affecting the normal use of silicone foam products.

[0003] In addition, during production and molding, solid silicone and high-temperature rubber foam cotton are cured at high temperature in the mold, which requires mold opening, and the continuous production efficiency is low.

[0004] Therefore, it is necessary to develop a hard silicone foam with good conformability, medium hardness and high elasticity, excellent high temperature aging resistance and small permanent deformation and a preparation method thereof. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a hard silicone foam and a preparation method thereof. The present invention uses hollow microspheres for filling and foaming, and is a liquid two-component addition-type silicone foam, which has the advantages of good conformability, medium hardness and high elasticity, excellent high temperature aging resistance, and small permanent deformation. It can be used for formation support in battery cell manufacturing, buffer protection in battery cell module assembly, and weight reduction, shock absorption, noise reduction, damping, flame retardancy, etc. of new energy vehicles.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A hard silicone foam comprises liquid A material and liquid B material; the mass ratio of the A material to the B material is 1:1; the liquid A material comprises the following components by weight: 60-100 parts of methyl vinyl siloxane, 5-45 parts of a reinforcing agent, and 0.05-3 parts of a platinum complex; the liquid B material comprises the following components by weight: 0.5-8 parts of hollow microspheres, 0.5-30 parts of hydrogen-containing silicone oil, and 5-25 parts of a flame retardant.

[0008] Preferably, the viscosity of the methyl vinyl siloxane is 1000-50000 cps, and the vinyl content is 0.12-0.32%.

[0009] Preferably, the reinforcing agent is precipitated white carbon black and / or gas phase white carbon black with a particle size of 5 to 50 nm.

[0010] Preferably, the platinum complex is a platinum catalyst whose main component is (0)-divinyltetramethyldisiloxane complex, wherein the Pt content is 5000-6000 ppm.

[0011] The hollow microspheres may be hollow glass microspheres. Preferably, the particle size of the hollow microspheres is 10 to 30 μm.

[0012] Preferably, the viscosity of the hydrogen-containing silicone oil is 50-1000 cps.

[0013] Preferably, the flame retardant is one or a combination of aluminum hydroxide nanoparticles, magnesium hydroxide nanoparticles, titanium oxide nanoparticles and montmorillonite, and the particle size of the flame retardant is 10 nm to 300 nm.

[0014] Another object of the present invention is to disclose a method for preparing the above-mentioned hard silicone foam, comprising the following steps:

[0015] (1) Mix liquid material A and material B, stir evenly, and obtain a mixed material AB;

[0016] (2) On a material unloading table provided with synchronously running upper and lower auxiliary material films, the mixed AB material is injected onto the upper surface of the lower auxiliary material film, and the upper auxiliary material film is covered on the mixed AB material, and then the mixed AB material is sent into a roller gap of a set height, and the mixed AB material between the upper and lower auxiliary material films is flattened by the relatively rotating rollers to form a rubber film layer; then the mixed AB material is sent into a segmented temperature-controlled oven to foam and solidify at 100 to 180° C., and the upper and lower auxiliary material films are separated after cooling, and the intermediate layer product is rolled up, and the rolled product is subjected to a second high-temperature treatment to obtain the hard silicone foam.

[0017] Preferably, the oven with segmented temperature control is a pulley-rotated parallel 12-stage oven, the temperature of the first 4 stages is set at 100-150°C, the 5th to 11th stages is set at 140-180°C, and the last stage is set at 80°C.

[0018] Preferably, the oven runs at a speed of 1.5 to 5 m / min.

[0019] Preferably, the secondary high temperature treatment is specifically: baking at 170-200° C. for 12-16 hours in a rolled state.

[0020] Preferably, the upper auxiliary material film is a non-silicone release film, and the surface of the auxiliary material film is a smooth surface or a frosted surface; the lower auxiliary material film is Teflon cloth, glass fiber cloth or a non-silicone release film, and the unwinding tension is 0.2-0.5 MPa.

[0021] Preferably, the thickness of the upper and lower auxiliary material films is 30-100 um, and the tensile strength is 5-10 kg.

[0022] Preferably, the rollers are a group of rotating rollers whose gaps can be adjusted by lifting and lowering, and the thickness of the product can be controlled by adjusting the gaps between the rollers.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention adjusts the thickness of the foam by relatively rotating rollers with adjustable gaps; the automatic feeding system controls the density of the foam by controlling the feeding speed and flow rate of the mixed AB materials, thereby controlling the hardness and rebound force of the foam; the film pressing method of the upper and lower films is used to ensure stable foaming and curing of the silicone foam and smooth demolding, and to give the foam surface a certain degree of roughness or smoothness; and through secondary high-temperature aging, a hard silicone foam material with a stable and uniform elliptical closed-cell structure, medium hardness, strong rebound force and excellent aging resistance is produced.

[0025] The hard silica foam prepared by the present invention has a product density of 0.70-1.00 g / cm 3 It has medium hardness, can provide sufficient rebound support, and has good conformability, which solves the problem of uneven force on existing solid silicone. It also has excellent aging resistance, with a permanent deformation rate of less than 5%, which solves the problem of excessive permanent thickness loss of existing high-temperature vulcanized rubber foam. At the same time, it has excellent flame retardancy, acid and alkali resistance, and high and low temperature resistance (-55 to 200°C), which can meet the special environmental requirements of the new energy industry.

[0026] The hard silicone foam preparation process of the present invention is stable and easy to implement, suitable for industrial continuous production, and has high production efficiency. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the examples, but it should be noted that the examples do not limit the scope of the present invention. The raw materials used in this example are all common commercial products.

[0028] Example 1

[0029] A hard silicone foam is prepared from the following liquid composition, which is composed of material A and material B in a mass ratio of 1:1. Material A includes the following components by weight: 70 parts of methyl vinyl siloxane, 30 parts of reinforcing agent, and 0.5 parts of platinum complex. Material B includes the following components by weight: 2 parts of hollow microspheres, 20 parts of hydrogen-containing silicone oil, and 10 parts of flame retardant.

[0030] The viscosity of methyl vinyl siloxane is 3000-4000 cps, and the vinyl content is 0.12-0.32%. The reinforcing agent is a composite of precipitated white carbon black with a particle size of 30 nm and fumed white carbon black with a particle size of 50 nm, and the mass ratio of precipitated white carbon black to fumed white carbon black is 4:1. The platinum complex is a platinum catalyst whose main component is a (0)-divinyltetramethyldisiloxane complex, wherein the Pt content is 5000-6000 ppm.

[0031] The hollow microspheres are hollow glass microspheres with a particle size of 10 to 30 μm. The hydrogen-containing silicone oil is terminal methyl hydrogen siloxane with a terminal hydrogen content of 1.5%, a side chain hydrogen content of 0.18%, and a viscosity of 50 to 1000 cps. The flame retardant is aluminum hydroxide nanoparticles with a particle size of 30 nm, titanium oxide nanoparticles with a particle size of 50 nm, and magnesium oxide nanoparticles with a particle size of 70 nm. The mass ratio of aluminum hydroxide nanoparticles, titanium oxide nanoparticles, and magnesium oxide nanoparticles is 3:1:1.

[0032] The preparation method of the above-mentioned hard silicone foam comprises the following steps:

[0033] (1) Mix material A and material B, stir evenly, and obtain a mixed material AB;

[0034] (2) Place the mixed AB material in an automatic feeding tank, install two sets of synchronous winding and unwinding devices at the winding and unwinding position, and install the upper and lower auxiliary material films at the upper and lower unwinding positions. Start the machine, open the material discharge valve, control the flow rate of the mixed AB material, inject the mixed AB material into the upper surface of the lower auxiliary material film, cover the mixed AB material with the upper auxiliary material film, adjust the gap between the upper and lower rollers, set it to 0.7mm, set the unwinding tension of the upper and lower auxiliary material films to 0.4MPa, and flatten and press the mixed AB material sandwiched between the upper and lower auxiliary material films through the relative rotation of the rollers to form a rubber film layer; then send it into a pulley-type parallel 12-section oven for foaming and curing. The temperatures of the first 4 sections of the oven are set to 100℃, 110℃, 110℃, and 120℃, and the 5th to 11th sections are set to 140℃, 140℃, 160℃, 170℃, 170℃, 170℃, and 170℃, and the last section is 80℃. The operating speed is 5m / min. After cooling, the upper and lower auxiliary film are separated, and the middle layer product is rolled up. The rolled product is subjected to a second high-temperature treatment: in a rolled state, it is baked at 180° C. for 12 hours to obtain the hard silicone foam.

[0035] The prepared hard silicone foam was subjected to different performance tests, and the results are shown in Table 1.

[0036] Example 2

[0037] A hard silicone foam is prepared from the following liquid composition, which is composed of material A and material B in a mass ratio of 1:1. Material A includes the following components by weight: 80 parts of methyl vinyl siloxane, 20 parts of a reinforcing agent, and 0.3 parts of a platinum complex. Material B includes the following components by weight: 8 parts of hollow microspheres, 15 parts of hydrogen-containing silicone oil, and 7 parts of a flame retardant.

[0038] The selection of the components in material A and material B is the same as in Example 1.

[0039] The preparation method of the above-mentioned hard silicone foam comprises the following steps:

[0040] (1) Mix material A and material B, stir evenly, and obtain a mixed material AB;

[0041] (2) Place the mixed AB material in an automatic feeding tank, install two sets of synchronous winding and unwinding devices at the winding and unwinding position, and install the upper and lower auxiliary material films at the upper and lower unwinding positions. Start the machine, open the material discharge valve, control the flow rate of the mixed AB material, inject the mixed AB material into the upper surface of the lower auxiliary material film, cover the mixed AB material with the upper auxiliary material film, adjust the gap between the upper and lower rollers to 0.7mm, set the unwinding tension of the upper and lower auxiliary material films to 0.4MPa, and flatten and press the mixed AB material sandwiched between the upper and lower auxiliary material films through the relative rotation of the rollers to form a rubber film layer; then send it into a pulley-type parallel 12-section oven for foaming and curing. The temperatures of the first 4 sections of the oven are set to 110℃, 120℃, 120℃, and 130℃, and the 5th to 11th sections are set to 150, 150℃, 170℃, 170℃, 160℃, 160℃, and 160℃, and the last section is 80℃. The operating speed is 3m / min. After cooling, the upper and lower auxiliary film are separated, and the middle layer product is rolled up. The rolled product is subjected to a second high-temperature treatment: in a rolled state, it is baked at 180° C. for 12 hours to obtain the hard silicone foam.

[0042] The prepared hard silicone foam was subjected to different performance tests, and the results are shown in Table 1.

[0043] Example 3

[0044] A hard silicone foam is prepared from the following liquid composition, which is composed of material A and material B in a mass ratio of 1:1. Material A includes the following components by weight: 100 parts of methyl vinyl siloxane, 30 parts of reinforcing agent, and 0.8 parts of platinum complex. Material B includes the following components by weight: 8 parts of hollow microspheres, 30 parts of hydrogen-containing silicone oil, and 5 parts of flame retardant.

[0045] The selection of the components in material A and material B is the same as in Example 1.

[0046] The preparation method of the hard silicone foam is the same as that of Example 2.

[0047] The prepared hard silicone foam was subjected to different performance tests, and the results are shown in Table 1.

[0048] Example 4

[0049] A hard silicone foam is prepared from the following liquid composition, which is composed of material A and material B in a mass ratio of 1:1. Material A includes the following components by weight: 100 parts of methyl vinyl siloxane, 10 parts of a reinforcing agent, and 0.8 parts of a platinum complex. Material B includes the following components by weight: 4 parts of hollow microspheres, 30 parts of hydrogen-containing silicone oil, and 5 parts of a flame retardant.

[0050] The selection of the components in material A and material B is the same as in Example 1.

[0051] The preparation method of the hard silicone foam is the same as that of Example 2.

[0052] The prepared hard silicone foam was subjected to different performance tests, and the results are shown in Table 1.

[0053] Comparative Example 1

[0054] In Comparative Example 1, the methyl vinyl siloxane in material A was adjusted to a viscosity of 5000-8000 cps and a vinyl content of 0.41-0.51%. Other raw materials, content ratios and the preparation method of the hard silicone foam were the same as those in Example 4.

[0055] Comparative Example 2

[0056] In Comparative Example 2, the methyl vinyl siloxane in material A was adjusted to a viscosity of 1000-2000 cps and a vinyl content of 0.08-0.12%. Other raw materials, content ratios and the preparation method of the hard silicone foam were the same as those in Example 4.

[0057] The physical and chemical properties of the hard silicone foams prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were tested according to the method specified in Table 1. The results are shown in Table 1.

[0058] Table 1 Product test results of Examples 1 to 4 and Comparative Examples 1 to 2

[0059]

[0060]

[0061] As can be seen from Table 1, the hard silicone foam of the present invention has strict requirements on the production formula and production process. Comparing Example 1 and Example 2, the formula and curing process are changed, and the product prepared in Example 2 has a higher density and more sufficient rebound force.

[0062] Compared with Example 3 and Example 4, changes were made to the fillers white carbon black and hollow microspheres added to the formula, so that the tensile strength and permanent deformation of the obtained product also changed.

[0063] Comparing Example 1 with Example 4, Example 1 changes the viscosity and vinyl content (increases) of methylvinylsiloxane, the main component of material A, and the permanent deformation (increases) and elongation (decreases) of the product of Example 1 are changed.

[0064] Comparing Example 2 with Example 4, Example 2 changes the viscosity and vinyl content (decreases) of methyl vinyl siloxane, the main component of material A, and the permanent deformation (increases), tensile strength (decreases), and density (increases) of the product of Example 2 are changed, while the comprehensive performance indicators of the product prepared in Example 4 are the best.

[0065] The above embodiments have provided a detailed introduction to the technical solutions provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A hard silicone foam, characterized in that: It comprises liquid material A and material B; the mass ratio of material A to material B is 1:1; the liquid material A comprises the following components by weight: 60-100 parts of methyl vinyl siloxane, 5-45 parts of reinforcing agent, and 0.05-3 parts of platinum complex; the liquid material B comprises the following components by weight: 0.5-8 parts of hollow microspheres, 0.5-30 parts of hydrogen-containing silicone oil, and 5-25 parts of flame retardant; The viscosity of the methylvinylsiloxane is 3000-4000cps, and the vinyl content is 0.12-0.32%; the reinforcing agent is precipitated white carbon black and / or gas phase white carbon black with a particle size of 5-50nm; the platinum complex is a platinum catalyst whose main component is (0)-divinyltetramethyldisiloxane complex, wherein the Pt content is 5000-6000ppm; The particle size of the hollow microspheres is 10 to 30 μm; the viscosity of the hydrogen-containing silicone oil is 50 to 1000 cps; the flame retardant is one or a combination of aluminum hydroxide nanoparticles, magnesium hydroxide nanoparticles, titanium oxide nanoparticles and montmorillonite, and the particle size of the flame retardant is 10 nm to 300 nm; The hard silicone foam is prepared by the following steps: (1) Mix liquid material A and material B, stir evenly, and obtain a mixed material AB; (2) On a material unloading table provided with synchronously running upper and lower auxiliary material films, the mixed AB material is injected onto the upper surface of the lower auxiliary material film, and the upper auxiliary material film is covered on the mixed AB material, and then the mixed AB material is sent into a roller gap of a set height, and the mixed AB material between the upper and lower auxiliary material films is flattened by the relatively rotating rollers to form a rubber film layer; then the mixed AB material is sent into a segmented temperature-controlled oven to foam and solidify at 100 to 180° C., and the upper and lower auxiliary material films are separated after cooling, and the intermediate layer product is rolled up, and the rolled product is subjected to a second high-temperature treatment to obtain the hard silicone foam.

2. The hard silicone foam according to claim 1, characterized in that: The oven with segmented temperature control is a belt-pulley type parallel 12-segment oven, the temperature of the first 4 segments is set at 100-150°C, the 5th to 11th segments are set at 140-180°C, and the last segment is set at 80°C.

3. The hard silicone foam according to claim 2, characterized in that: The oven runs at a speed of 1.5-5 m / min.

4. The hard silicone foam according to claim 1, characterized in that: The secondary high temperature treatment is specifically: baking at 170-200° C. for 12-16 hours in a rolled state.

5. The hard silicone foam according to claim 1, characterized in that: The upper auxiliary material film is a non-silicone release film, and the surface of the auxiliary material film is a smooth surface or a frosted surface; the lower auxiliary material film is Teflon cloth, glass fiber cloth or a non-silicone release film, and the unwinding tension is 0.2-0.5MPa.

6. The hard silicone foam according to claim 1, characterized in that: The thickness of the upper and lower auxiliary material films is 30-100 um, and the tensile strength is 5-10 kg.

7. The hard silicone foam according to claim 1, characterized in that: The rollers are a group of rotating rollers whose gaps can be adjusted by lifting and lowering.

Images