Two-component polyurethane thermally conductive gel and preparation method therefor

Abstract

The present invention provides a two-component polyurethane thermally conductive gel, which consists of component A and component B at a volume ratio of (0.8-1.2):1. Component A comprises: 5-15 parts by weight of polyol; 1-10 parts by weight of plasticizer; 80-95 parts by weight of thermally conductive powder; 0.1-1 part by weight of dispersant; 0.1-1 part by weight of catalyst; and 0.1-1 part by weight of yellow color paste. Component B comprises: 2-10 parts by weight of isocyanate; 2-10 parts by weight of polyol; 2-10 parts by weight of plasticizer; 80-95 parts by weight of thermally conductive powder; 0.1-1 part by weight of anti-aging agent; 0.1-1 part by weight of dispersant; 0.1-1 part by weight of water absorbent; and 0.1-1 part by weight of blue color paste. Compared with the prior art, the two-component polyurethane thermally conductive gel provided by the present invention adopts specific components in specific contents to achieve overall favorable interaction, can meet requirements for non-silicone thermal interface materials, and has excellent high-temperature resistance and low thermal conductivity.

Description

A two-component polyurethane thermal conductive gel and its preparation method

[0001] This application claims priority to Chinese Patent Application No. 202411586559.7, filed on November 8, 2024, entitled "A Two-Component Polyurethane Thermal Conductive Gel and Its Preparation Method", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of thermal conductive gel technology, and more specifically, to a two-component polyurethane thermal conductive gel and its preparation method. Background Technology

[0003] Currently, thermal interface materials play an irreplaceable role in fields such as new energy vehicle power batteries and consumer electronics. Thermal interface materials are materials capable of conducting heat away from a heat source, requiring high thermal conductivity and a thin profile. Simultaneously, because thermal interface materials are in direct contact with the heat source, they are exposed to high temperatures for extended periods, placing stringent requirements on their high-temperature resistance. Currently, commonly used products on the market include thermal pads, thermal gels, and thermal greases made from silicone resins. Due to their good temperature resistance and softness, silicone products are more suitable for practical industrial applications. Other resins such as polyurethane, epoxy, and acrylic are not currently used.

[0004] However, silicone-based products face an intractable problem: environmental friendliness. It is well known that silicone resins contain D4-D10 silicone cyclic molecules, which are prone to leaching and causing environmental harm. The European Union has gradually begun to restrict the use of silicone materials, and the adoption of non-silicone thermal interface materials to replace traditional silicone thermal interface materials by downstream customers has become an emerging field.

[0005] In recent years, to address the aforementioned issues, existing technologies have emerged that employ single-component MS (modified silane) adhesives for the preparation of thermally conductive gels. Silane-modified polymers, by retaining siloxane groups only at the polymer ends, avoid the formation of organosilicon rings. However, single-component MS thermally conductive gels still present two problems: first, silicon is still present in the system, failing to achieve true silicon-free properties; second, the curing method of single-component MS thermally conductive gels is moisture curing, which, in the encapsulation of electronic components, may lead to incomplete curing due to the inability to contact with air, potentially posing safety hazards. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a two-component polyurethane thermal conductive gel and its preparation method. The two-component polyurethane thermal conductive gel provided by this invention is based on a polyurethane system, which can meet the requirements for non-silicon thermal interface materials. At the same time, the product has excellent high temperature resistance and low thermal conductivity.

[0007] This invention provides a two-component polyurethane thermally conductive gel, composed of component A and component B in a volume ratio of (0.8-1.2):1;

[0008] Component A includes:

[0009] 5 to 15 parts by weight of polyol;

[0010] Plasticizer 1 part by weight to 10 parts by weight;

[0011] 80 to 95 parts by weight of thermal conductive powder;

[0012] Dispersant: 0.1 parts by weight to 1 part by weight;

[0013] Catalyst: 0.1 parts by weight to 1 part by weight;

[0014] 0.1 to 1 part by weight of yellow pigment;

[0015] Component B includes:

[0016] 2 to 10 parts by weight of isocyanate;

[0017] 2 to 10 parts by weight of polyol;

[0018] Plasticizer 2 to 10 parts by weight;

[0019] 80 to 95 parts by weight of thermal conductive powder;

[0020] Anti-aging agent: 0.1 to 1 part by weight;

[0021] Dispersant: 0.1 parts by weight to 1 part by weight;

[0022] 0.1 to 1 part by weight of absorbent;

[0023] 0.1 to 1 part by weight of blue pigment.

[0024] Preferably, the polyol is a flexible aliphatic modified castor oil polyol.

[0025] Preferably, the plasticizer is a hydrocarbon-based high-boiling-point plasticizer.

[0026] Preferably, the thermal conductive powder is selected from one or more of Jinge JAZ-386, Jinge JAZ-387, and Zexi CCG060D08G.

[0027] Preferably, the dispersant is selected from BYK BYK-9076 and / or BYK BYK-145.

[0028] Preferably, the catalyst is selected from Umicore Valikat Bi1610 and / or Vertellus Coscat 83.

[0029] Preferably, the isocyanate is an aliphatic polyisocyanate;

[0030] The absorbent is selected from Borchers TI and / or LANXESS Trixene ASF.

[0031] This invention also provides a method for preparing the two-component polyurethane thermally conductive gel described in the above technical solution, comprising the following steps:

[0032] a) The polyol, plasticizer, and thermally conductive powder are heated to 110℃~130℃ and mixed, then vacuum dehydrated. The mixture is then cooled to below 50℃ and added with dispersant, catalyst, and yellow pigment paste. The mixture is then vacuum mixed to obtain component A.

[0033] b) After the isocyanate, dehydrated polyol, and plasticizer undergo a first reaction, the dried thermally conductive powder, antioxidant, dispersant, water absorbent, and blue pigment are added for a second reaction to obtain component B.

[0034] c) Mix the above components A and B at a volume ratio of (0.8 to 1.2):1 to obtain a two-component polyurethane thermal conductive gel;

[0035] There is no order restriction between steps a) and b).

[0036] Preferably, the heating to 110°C to 130°C and mixing in step a) is done by stirring, and the stirring speed is 400 rpm to 600 rpm;

[0037] The vacuum degree of the vacuum dehydration is -0.08MPa to -0.1MPa, and the time is 1.5h to 2.5h;

[0038] The vacuum mixing process involves a vacuum level of -0.08 MPa to -0.1 MPa, a rotation speed of 50 rpm to 150 rpm, and a mixing time of 30 min to 60 min.

[0039] Preferably, the temperature of the first reaction in step b) is 70℃~90℃, the rotation speed is 80rpm~120rpm, the vacuum degree is -0.08MPa~-0.1MPa, and the time is 1.5h~2.5h;

[0040] The second reaction was carried out at a temperature of 10℃ to 40℃, a rotation speed of 180 rpm to 220 rpm, a vacuum degree of -0.08 MPa to -0.1 MPa, and a time of 0.5 h to 1.5 h.

[0041] This invention provides a two-component polyurethane thermally conductive gel, composed of component A and component B in a volume ratio of (0.8-1.2):1. Component A includes: 5-15 parts by weight of polyol; 1-10 parts by weight of plasticizer; 80-95 parts by weight of thermally conductive powder; 0.1-1 parts by weight of dispersant; 0.1-1 parts by weight of catalyst; and 0.1-1 parts by weight of yellow pigment. Component B includes: 2-10 parts by weight of isocyanate; 2-10 parts by weight of polyol; 2-10 parts by weight of plasticizer; 80-95 parts by weight of thermally conductive powder; 0.1-1 parts by weight of anti-aging agent; 0.1-1 parts by weight of dispersant; 0.1-1 parts by weight of water-absorbing agent; and 0.1-1 parts by weight of blue pigment. Compared with the prior art, the two-component polyurethane thermal conductive gel provided by the present invention uses specific components in specific amounts to achieve better overall interaction, which can meet the requirements for non-silicon thermal interface materials. At the same time, the product has excellent high temperature resistance and low thermal conductivity.

[0042] Furthermore, the preparation method provided by this invention is simple, mild, and easy to control, with low equipment requirements, and has broad application prospects. Attached Figure Description

[0043] Figure 1 shows the hardness change curves of PCT aging (120℃ / 100% RH / 0.2MPa) in Examples 1-3;

[0044] Figure 2 shows the hardness change curves of Examples 1-3 after high temperature and high humidity aging (85℃ / 85%RH);

[0045] Figure 3 shows the hardness change curves of high-temperature aging (150℃ / 50%RH) in Examples 1-3. Detailed Implementation

[0046] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0047] This invention provides a two-component polyurethane thermally conductive gel, composed of component A and component B in a volume ratio of (0.8-1.2):1;

[0048] Component A includes:

[0049] 5 to 15 parts by weight of polyol;

[0050] Plasticizer 1 part by weight to 10 parts by weight;

[0051] 80 to 95 parts by weight of thermal conductive powder;

[0052] Dispersant: 0.1 parts by weight to 1 part by weight;

[0053] Catalyst: 0.1 parts by weight to 1 part by weight;

[0054] 0.1 to 1 part by weight of yellow pigment;

[0055] Component B includes:

[0056] 2 to 10 parts by weight of isocyanate;

[0057] 2 to 10 parts by weight of polyol;

[0058] Plasticizer 2 to 10 parts by weight;

[0059] 80 to 95 parts by weight of thermal conductive powder;

[0060] Anti-aging agent: 0.1 to 1 part by weight;

[0061] Dispersant: 0.1 parts by weight to 1 part by weight;

[0062] 0.1 to 1 part by weight of absorbent;

[0063] 0.1 to 1 part by weight of blue pigment.

[0064] This invention provides a two-component polyurethane thermal conductive gel, which solves the problem that existing thermal conductive gels are all organosilicon systems and cannot meet the requirement that the adhesive does not contain free silicone. This invention uses polyurethane to replace silicone as the thermal conductive gel. First, the hardness issue needs to be addressed. In practical applications, the hardness of the thermal conductive gel cannot be too high. Currently used products have a hardness in the Shore-00 range of 50-70. For silicone, due to its soft and low-polarity chain segments, low hardness can be achieved relatively easily. However, for polyurethane systems, due to their higher polarity and the rigidity of urethane segments in the molecular chain, achieving Shore-00 level hardness is difficult. Second, the amount of thermal conductive powder added needs to be addressed. Thermal conductive gels require high thermal conductivity, typically greater than 3.0 W / m·K. The high viscosity of polyurethane systems limits the amount of thermal conductive powder that can be added, making it difficult to achieve high thermal conductivity. Third, the weather resistance of the polyurethane adhesive is crucial. The thermal conductive gel is in direct contact with the heat source, requiring high resistance to high temperature and humidity. The adhesive must not crack, powder, or undergo drastic changes in hardness after aging under high temperature and humidity.

[0065] To address the aforementioned technical problems and obtain a thermally conductive gel that meets the requirements, this invention takes the following approaches: selecting aliphatic isocyanates to reduce the NCO content of the prepolymer, increase the length of the prepolymer chains, and improve the flexibility of the adhesive; selecting suitable plasticizers to further reduce the hardness of the adhesive and the viscosity of the system, thereby increasing the amount of thermally conductive powder added; selecting highly efficient wetting and dispersing agents to reduce the viscosity of the system and increase the amount of thermally conductive powder added; and selecting suitable polyol resins to improve the weather resistance of the adhesive.

[0066] In this invention, the two-component polyurethane thermal conductive gel is composed of component A and component B with a volume ratio of (0.8 to 1.2):1, preferably 1:1.

[0067] In this invention, component A comprises:

[0068] 5 to 15 parts by weight of polyol;

[0069] Plasticizer 1 part by weight to 10 parts by weight;

[0070] 80 to 95 parts by weight of thermal conductive powder;

[0071] Dispersant: 0.1 parts by weight to 1 part by weight;

[0072] Catalyst: 0.1 parts by weight to 1 part by weight;

[0073] 0.1 to 1 part by weight of yellow pigment;

[0074] Preferably prepared from raw materials containing the following components:

[0075] 5 to 10 parts by weight of polyol;

[0076] Plasticizer 1 part to 3 parts by weight;

[0077] 85 to 92 parts by weight of thermal conductive powder;

[0078] Dispersant: 0.5 parts by weight to 1 part by weight;

[0079] Catalyst: 0.5 parts by weight to 1 part by weight;

[0080] 0.4 to 0.6 parts by weight of yellow pigment.

[0081] In this invention, the polyol is preferably a flexible aliphatic modified castor oil polyol; the flexible aliphatic modified castor oil polyol is preferably selected from Itoh Oil URIC 4048U and / or Itoh Oil URIC PH-100D, more preferably Itoh Oil URIC 4048U or Itoh Oil URIC PH-100D. This invention does not impose any special restrictions on the source of the polyol; commercially available products well known to those skilled in the art can be used.

[0082] In this invention, the plasticizer is preferably a hydrocarbon-based high-boiling-point plasticizer; the hydrocarbon-based high-boiling-point plasticizer is preferably Rutgers Ruetasolv DI and / or Rutgers Ruetasolv BP D, more preferably Rutgers Ruetasolv DI or Rutgers Ruetasolv BP D. This invention does not impose any special restrictions on the source of the plasticizer; commercially available products well-known to those skilled in the art can be used.

[0083] In this invention, the thermal conductive powder is preferably selected from one or more of Jinge JAZ-386, Jinge JAZ-387, and Zexi CCG060D08G, more preferably Jinge JAZ-386, Jinge JAZ-387, or Zexi CCG060D08G. This invention does not impose any special restrictions on the source of the thermal conductive powder; commercially available products well-known to those skilled in the art can be used.

[0084] In this invention, the dispersant is preferably selected from BYK BYK-9076 and / or BYK BYK-145, more preferably BYK BYK-9076 or BYK BYK-145. This invention does not impose any special restrictions on the source of the dispersant; commercially available products well-known to those skilled in the art can be used.

[0085] In this invention, the catalyst is preferably selected from Umicore Valikat Bi1610 and / or Vertellus Coscat 83, more preferably Umicore Valikat Bi1610 or Vertellus Coscat 83. This invention does not impose any particular limitation on the source of the catalyst; commercially available products well-known to those skilled in the art can be used.

[0086] In this invention, the yellow pigment can be any commercially available product known to those skilled in the art, and there are no special restrictions on it.

[0087] In this invention, component B comprises:

[0088] 2 to 10 parts by weight of isocyanate;

[0089] 2 to 10 parts by weight of polyol;

[0090] Plasticizer 2 to 10 parts by weight;

[0091] 80 to 95 parts by weight of thermal conductive powder;

[0092] Anti-aging agent: 0.1 to 1 part by weight;

[0093] Dispersant: 0.1 parts by weight to 1 part by weight;

[0094] 0.1 to 1 part by weight of absorbent;

[0095] 0.1 to 1 part by weight of blue pigment;

[0096] Preferably prepared from raw materials containing the following components:

[0097] 2 to 4 parts by weight of isocyanate;

[0098] 4 to 8 parts by weight of polyol;

[0099] Plasticizer 3 to 5 parts by weight;

[0100] 82 to 90 parts by weight of thermal conductive powder;

[0101] Anti-aging agent: 0.1 to 0.2 parts by weight;

[0102] Dispersant: 0.4 parts by weight to 0.6 parts by weight;

[0103] Absorbent: 0.1 to 0.2 parts by weight;

[0104] 0.1 to 0.2 parts by weight of blue pigment.

[0105] In this invention, the polyol, plasticizer, thermally conductive powder and dispersant are the same as those in component A above, and will not be described again here.

[0106] In this invention, the isocyanate is preferably an aliphatic polyisocyanate; the aliphatic polyisocyanate is preferably Desmodur N100 and / or 4,4'-dicyclohexylmethane diisocyanate (H12MDI), more preferably Desmodur N100 or H12MDI. This invention does not impose any particular restrictions on the source of the isocyanate; commercially available products well known to those skilled in the art can be used.

[0107] In this invention, the anti-aging agent is preferably selected from double-bonded Chinox TP-10H and / or BASF Irganox B215, more preferably double-bonded Chinox TP-10H or BASF Irganox B215. This invention does not impose any special restrictions on the source of the anti-aging agent; commercially available products well-known to those skilled in the art can be used.

[0108] In this invention, the absorbent is preferably selected from Borchers TI and / or LANXESS Trixene ASF, more preferably Borchers TI or LANXESS Trixene ASF. This invention does not impose any particular limitation on the source of the absorbent; commercially available products well known to those skilled in the art can be used.

[0109] In this invention, the blue pigment can be any commercially available product known to those skilled in the art, and there are no special restrictions on it.

[0110] The two-component polyurethane thermal conductive gel provided by this invention utilizes specific components in specific amounts to achieve good overall interaction, meeting the requirements for non-silicon thermal interface materials. Simultaneously, the product exhibits excellent high-temperature resistance and low thermal conductivity. Experimental results show that the two-component polyurethane thermal conductive gel provided by this invention has low hardness (50–70 Shore-00 range), high thermal conductivity (3.0–4.0 W / m·K), convenient construction, high extrudability, and excellent high-temperature / humidity heat resistance. After three aging tests—PCT (high-pressure cooking aging, 120℃ / 100% RH / 0.2MPa) 72h, high-temperature and high-humidity (85℃ / 85% RH) 1000h, and high-temperature (150℃ / 50% RH) 1000h—it maintained both performance and appearance.

[0111] This invention also provides a method for preparing the two-component polyurethane thermally conductive gel described in the above technical solution, comprising the following steps:

[0112] a) The polyol, plasticizer, and thermally conductive powder are heated to 110℃~130℃ and mixed, then vacuum dehydrated. The mixture is then cooled to below 50℃ and added with dispersant, catalyst, and yellow pigment paste. The mixture is then vacuum mixed to obtain component A.

[0113] b) After the isocyanate, dehydrated polyol, and plasticizer undergo a first reaction, the dried thermally conductive powder, antioxidant, dispersant, water absorbent, and blue pigment are added for a second reaction to obtain component B.

[0114] c) Mix the above components A and B at a volume ratio of (0.8 to 1.2):1 to obtain a two-component polyurethane thermal conductive gel;

[0115] There is no order restriction between steps a) and b).

[0116] In this invention, the raw materials described above are the same as those described in the above technical solutions, and will not be repeated here.

[0117] In this invention, the heating to 110°C to 130°C and mixing method in step a) is preferably stirring, and the stirring speed is preferably 400 rpm to 600 rpm, more preferably 500 rpm; the vacuum degree of the vacuum dehydration is preferably -0.08 MPa to -0.1 MPa, and the time is preferably 1.5 h to 2.5 h; the vacuum degree of the vacuum mixing is preferably -0.08 MPa to -0.1 MPa, the stirring speed is preferably 50 rpm to 150 rpm, more preferably 100 rpm, and the time is preferably 30 min to 60 min.

[0118] In this invention, the temperature of the first reaction in step b) is preferably 70℃~90℃, more preferably 80℃, the rotation speed is preferably 80rpm~120rpm, more preferably 100rpm, the vacuum degree is preferably -0.08MPa~-0.1MPa, and the time is preferably 1.5h~2.5h; the temperature of the second reaction is preferably 10℃~40℃, more preferably 20℃~30℃, the rotation speed is preferably 180rpm~220rpm, more preferably 200rpm, the vacuum degree is preferably -0.08MPa~-0.1MPa, and the time is preferably 0.5h~1.5h.

[0119] In this invention, the drying process described in step b) is preferably as follows:

[0120] The thermally conductive powder is dried and dehydrated in an oven at 90℃~110℃ for 45h~50h to obtain the dried thermally conductive powder.

[0121] In this invention, the dehydration process described in step b) is preferably as follows:

[0122] The polyol and plasticizer were dehydrated at 110℃~130℃ under vacuum to -0.08MPa~-0.1MPa for 1.5h~2.5h to obtain the dehydrated polyol and plasticizer.

[0123] The preparation method provided by this invention is simple, has mild and easy-to-control conditions, does not require high-end equipment, and has broad application prospects.

[0124] This invention provides a two-component polyurethane thermally conductive gel, composed of component A and component B in a volume ratio of (0.8-1.2):1. Component A includes: 5-15 parts by weight of polyol; 1-10 parts by weight of plasticizer; 80-95 parts by weight of thermally conductive powder; 0.1-1 parts by weight of dispersant; 0.1-1 parts by weight of catalyst; and 0.1-1 parts by weight of yellow pigment. Component B includes: 2-10 parts by weight of isocyanate; 2-10 parts by weight of polyol; 2-10 parts by weight of plasticizer; 80-95 parts by weight of thermally conductive powder; 0.1-1 parts by weight of anti-aging agent; 0.1-1 parts by weight of dispersant; 0.1-1 parts by weight of water-absorbing agent; and 0.1-1 parts by weight of blue pigment. Compared with the prior art, the two-component polyurethane thermal conductive gel provided by the present invention uses specific components in specific amounts to achieve better overall interaction, which can meet the requirements for non-silicon thermal interface materials. At the same time, the product has excellent high temperature resistance and low thermal conductivity.

[0125] Furthermore, the preparation method provided by this invention is simple, mild, and easy to control, with low equipment requirements, and has broad application prospects.

[0126] To further illustrate the present invention, the following embodiments are provided for detailed description. The raw materials involved in the following embodiments of the present invention are as follows:

[0127] Polyols: Flexible aliphatic modified castor oil polyols, Itoh Oil URIC 4048U, Itoh Oil URIC PH-100D;

[0128] Plasticizers: Hydrocarbon high-boiling-point plasticizers, Rutgers Ruetasolv DI, Rutgers Ruetasolv BP D;

[0129] Thermal conductive powder: Jinge JAZ-386, Jinge JAZ-387, Zexi CCG060D08G;

[0130] Dispersants: BYK BYK-9076, BYK BYK-145;

[0131] Catalysts: Umicore Valikat Bi1610, Vertellus Coscat 83;

[0132] Yellow pigment: Baomeishi 085-1I4215;

[0133] Isocyanates: Covestro aliphatic polyisocyanate (HDI biuret) Desmodur N 100, Wanhua 4,4'-dicyclohexylmethane diisocyanate (H12MDI);

[0134] Anti-aging agents: Chinox TP-10H (Taiwan), BASF Irganox B215;

[0135] Absorbents: Borchers TI, LANXESS Trixene ASF;

[0136] Blue pigment: Baomeishi 085-5M4214.

[0137] Example 1

[0138] Component A: 10 parts by weight of URIC PH-100D polyol, 3 parts by weight of Ruetasolv BPD plasticizer, 85 parts by weight of CCG060D08G thermal conductive powder, 0.5 parts by weight of BYK-9076 dispersant, 1 part by weight of Valikat Bi1610 catalyst, and 0.5 parts by weight of yellow pigment.

[0139] Component B: 4 parts by weight of Desmodur N100 isocyanate, 8 parts by weight of URIC PH-100D polyol, 5 parts by weight of Ruetasolv BPD plasticizer, 82 parts by weight of CCG060D08G thermal conductive powder, 0.2 parts by weight of Chinox TP-10H anti-aging agent, 0.5 parts by weight of BYK-9076 dispersant, 0.1 parts by weight of TI water absorbent, and 0.2 parts by weight of blue pigment.

[0140] Example 2

[0141] Component A: 8 parts by weight of URIC PH-100D polyol, 2 parts by weight of Ruetasolv DI plasticizer, 88 parts by weight of JAZ-386 thermal conductive powder, 0.5 parts by weight of BYK-145 dispersant, 1 part by weight of Valikat Bi1610 catalyst, and 0.5 parts by weight of yellow pigment.

[0142] Component B: 3 parts by weight of H12MDI isocyanate, 6 parts by weight of URIC 4048U polyol, 5 parts by weight of Ruetasolv DI plasticizer, 85 parts by weight of JAZ-386 thermal conductive powder, 0.2 parts by weight of Chinox TP-10H anti-aging agent, 0.5 parts by weight of BYK-145 dispersant, 0.1 parts by weight of TI water absorbent, and 0.2 parts by weight of blue pigment.

[0143] Example 3

[0144] Component A: 5 parts by weight of URIC 4048U polyol, 1 part by weight of Ruetasolv DI plasticizer, 92 parts by weight of JAZ-387 thermal conductive powder, 0.5 parts by weight of BYK-145 dispersant, 1 part by weight of Coscat 83 catalyst, and 0.5 parts by weight of yellow pigment.

[0145] Component B: 2 parts by weight of H12MDI isocyanate, 4 parts by weight of URIC 4048U polyol, 3 parts by weight of Ruetasolv DI plasticizer, 90 parts by weight of JAZ-387 thermal conductive powder, 0.2 parts by weight of Irganox B215 anti-aging agent, 0.5 parts by weight of BYK-145 dispersant, 0.1 parts by weight of Trixene ASF water absorbent, and 0.2 parts by weight of blue pigment.

[0146] The above formula is shown in Table 1 below.

[0147] Table 1

[0148] The specific preparation methods of the two-component polyurethane thermally conductive gels provided in the above embodiments are as follows:

[0149] Component A:

[0150] Polyol, plasticizer, and thermally conductive powder were heated to 120°C with stirring at 500 rpm, and then vacuumed to -0.09 MPa for 2 hours to dehydrate. Then, the mixture was cooled to below 50°C, and dispersant, catalyst, and yellow pigment were added. Vacuuming was then carried out to below -0.09 MPa, and stirring was continued at 100 rpm for 40 minutes to obtain component A.

[0151] Component B:

[0152] First, dry and dehydrate the thermally conductive powder in a 100℃ drying oven for 48 hours, then set it aside.

[0153] The polyol and plasticizer were dehydrated at 120℃ under vacuum to -0.09MPa for 2 hours and then set aside.

[0154] Then, isocyanate, pre-dehydrated polyol, and plasticizer were stirred at 100 rpm at 80°C and vacuumed to -0.09 MPa for 2 hours. Subsequently, pre-dried thermal conductive powder, anti-aging agent, dispersant, water absorbent, and blue pigment were added. The mixture was stirred at 200 rpm at room temperature and vacuumed to -0.09 MPa for 1 hour to obtain component B.

[0155] Finally, the components A and B were mixed evenly at a volume ratio of 1:1 to obtain a two-component polyurethane thermal conductive gel.

[0156] The properties of the two-component polyurethane thermal conductive gels provided in each embodiment were tested, and the test standards / methods are as follows:

[0157] Density: ASTM D792, Test Method for Density and Relative Density of Plastics;

[0158] Hardness: ASTM D2240, the standard test method for hardness of a hardness tester;

[0159] Thermal conductivity: ASTM D5470, Standard Test Method for Thermal Conductivity of Thermally Conductive Insulating Materials;

[0160] Volume resistivity: ASTM D257, standard test method for DC resistance or conductance of insulating materials;

[0161] Breakdown voltage: ASTM D149, Test method for dielectric breakdown voltage and dielectric strength of solid electrical insulating materials at industrial power frequencies;

[0162] PCT aging (120℃ / 100% RH / 0.2MPa): IEC60068-2-66, Environmental testing-Part 2: Test methods-Test Cx: Damp heat, steady state (unsaturated pressurized vapour);

[0163] High temperature and high humidity aging (85℃ / 85%RH): GB / T 2423.50-2012, Environmental testing of electrical and electronic products - Part 2: Test methods. Constant damp heat is mainly used for accelerated testing of components.

[0164] High temperature aging (150℃ / 50%RH): GB / T 2423.50-2012, Environmental testing of electrical and electronic products - Part 2: Test methods. Constant damp heat is mainly used for accelerated testing of components.

[0165] Some test results are shown in Table 2 below.

[0166] Table 2

[0167] In Table 2, control 1 adhesive is a two-component silicone thermal conductive gel, Hangzhou Zhijiang ZJ-DR6200-4; control 2 adhesive is a one-component MS thermal conductive gel, Zhejiang Sanyuan SG450F.

[0168] The hardness change curves for PCT aging (120℃ / 100% RH / 0.2MPa) are shown in Figure 1; the hardness change curves for high temperature and high humidity aging (85℃ / 85% RH) are shown in Figure 2; and the hardness change curves for high temperature aging (150℃ / 50% RH) are shown in Figure 3.

[0169] Experimental results show that the two-component polyurethane thermal conductive gel provided by this invention firstly increases the overall chain length by preparing an isocyanate prepolymer with low NCO content, thereby increasing the flexibility and reducing the hardness of the adhesive; secondly, by selecting a suitable thermal conductive powder and dispersant combination, the viscosity of the system is reduced, and the amount of thermal conductive powder added is increased, thereby improving the extrudability of the adhesive; thirdly, by selecting a suitable flexible polyol, the hardness of the adhesive is further reduced, and by combining a suitable anti-aging agent and high-temperature plasticizer, the weather resistance of the adhesive is improved. The results show that, through reasonable raw material selection, the thermal conductive gel prepared using the polyurethane system can achieve a thermal conductivity of up to 4.5 W / m / k and a hardness controlled below 70 Shore-00, which is basically consistent with that of silicone. More importantly, the polyurethane thermal conductive gel possesses excellent aging resistance and high-temperature resistance. Whether under extreme PCT aging or high-temperature aging at 150°C, the adhesive did not exhibit cracking, powdering, or other abnormal phenomena, and its hardness was well maintained.

[0170] In summary, this invention has achieved the development of non-silicone thermal conductive gels through reasonable formulation design, thus solving the shortcomings of polyurethane thermal conductive gels such as poor high-temperature resistance and low thermal conductivity.

[0171] The two-component polyurethane water-blocking adhesive reduces the water vapor transmission rate of the system by adding liquid polybutadiene polyol, and improves its resistance to ultraviolet radiation by adding antioxidants. More importantly, the addition of asphalt has a positive effect on the system; as the amount of asphalt added increases, the water vapor transmission rate gradually decreases, flexibility increases, and resistance to PCT / UV irradiation aging improves. However, it is worth noting that excessive asphalt addition will reduce the system's hardness and bond strength. Experimental results show that an addition of 20wt% is optimal; further increasing to 30wt% results in lower shear strength. Comparative experiments show that without asphalt, the system's UV resistance is significantly reduced.

[0172] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A two-component polyurethane thermally conductive gel, comprising component A and component B in a volume ratio of (0.8–1.2):1; Component A includes: 5 to 15 parts by weight of polyol; Plasticizer 1 part by weight to 10 parts by weight; 80 to 95 parts by weight of thermal conductive powder; Dispersant: 0.1 parts by weight to 1 part by weight; Catalyst: 0.1 parts by weight to 1 part by weight; 0.1 to 1 part by weight of yellow pigment; Component B includes: 2 to 10 parts by weight of isocyanate; 2 to 10 parts by weight of polyol; Plasticizer 2 to 10 parts by weight; 80 to 95 parts by weight of thermal conductive powder; Anti-aging agent: 0.1 to 1 part by weight; Dispersant: 0.1 parts by weight to 1 part by weight; 0.1 to 1 part by weight of absorbent; 0.1 to 1 part by weight of blue pigment.

2. The two-component polyurethane thermally conductive gel according to claim 1, characterized in that, The polyol is a flexible aliphatic modified castor oil polyol.

3. The two-component polyurethane thermally conductive gel according to claim 1, characterized in that, The plasticizer is a hydrocarbon-based high-boiling-point plasticizer.

4. The two-component polyurethane thermally conductive gel according to claim 1, characterized in that, The thermal conductive powder is selected from one or more of Jinge JAZ-386, Jinge JAZ-387, and Zexi CCG060D08G.

5. The two-component polyurethane thermally conductive gel according to claim 1, characterized in that, The dispersant is selected from BYK BYK-9076 and / or BYK BYK-145.

6. The two-component polyurethane thermally conductive gel according to claim 1, characterized in that, The catalyst is selected from Umicore Valikat Bi1610 and / or Vertellus Coscat 83.

7. The two-component polyurethane thermally conductive gel according to claim 1, characterized in that, The isocyanate is an aliphatic polyisocyanate; The absorbent is selected from Borchers TI and / or LANXESS Trixene ASF.

8. A method for preparing a two-component polyurethane thermally conductive gel according to any one of claims 1 to 7, comprising the following steps: a) The polyol, plasticizer, and thermally conductive powder are heated to 110℃~130℃ and mixed, then vacuum dehydrated. The mixture is then cooled to below 50℃ and added with dispersant, catalyst, and yellow pigment paste. The mixture is then vacuum mixed to obtain component A. b) After the isocyanate, dehydrated polyol, and plasticizer undergo a first reaction, the dried thermally conductive powder, antioxidant, dispersant, water absorbent, and blue pigment are added for a second reaction to obtain component B. c) Mix the above components A and B at a volume ratio of (0.8 to 1.2):1 to obtain a two-component polyurethane thermal conductive gel; There is no order restriction between steps a) and b).

9. The preparation method according to claim 8, characterized in that, The mixing method described in step a) of heating to 110℃~130℃ is stirring, and the stirring speed is 400rpm~600rpm; The vacuum degree of the vacuum dehydration is -0.08MPa to -0.1MPa, and the time is 1.5h to 2.5h; The vacuum mixing process involves a vacuum level of -0.08 MPa to -0.1 MPa, a rotation speed of 50 rpm to 150 rpm, and a mixing time of 30 min to 60 min.

10. The preparation method according to claim 8, characterized in that, The temperature of the first reaction in step b) is 70℃~90℃, the rotation speed is 80rpm~120rpm, the vacuum degree is -0.08MPa~-0.1MPa, and the time is 1.5h~2.5h; The second reaction was carried out at a temperature of 10℃ to 40℃, a rotation speed of 180 rpm to 220 rpm, a vacuum degree of -0.08 MPa to -0.1 MPa, and a time of 0.5 h to 1.5 h.

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