WO2023109162A1 - Polyurethane structural adhesive and preparation method therefor - Google Patents

Abstract

The present invention provides a polyurethane structural adhesive, used for being bonded to a PET film material, and comprising a first component and a second component; the first component comprises a prepolymer, a first thermally conductive filler, and a first tackifier; the second component comprises a polyester polyol, a second thermally conductive filler, and a second tackifier; the prepolymer consists of isocyanate and a polycaprolactone polyol; the isocyanate consists of an HDI trimer and modified MDI; the polyester polyol consists of a polycaprolactone polyol and modified castor oil; the volume ratio of the first component to the second component is (0.9-1.1):(0.9-1.1). The polyurethane structural adhesive of the present invention solves the problem of being easy to cause an adhesive failure during the process of use after the polyurethane structural adhesive is bonded to the PET film material, and the peel strength between the polyurethane structural adhesive and the PET film material is greater than 1 N/mm. The present invention also provides a preparation method for the polyurethane structural adhesive.

Description

Polyurethane structural adhesive and preparation method thereof

cross reference

This application claims the priority of the Chinese Patent Application No. 2021115444378 filed on December 16, 2021. The content of the above application is incorporated herein by reference.

technical field

The invention relates to the technical field of polyurethane, in particular to a polyurethane structural adhesive and a preparation method thereof.

Background technique

Polyurethane is the abbreviation of polyurethane, and its English name is polyurethane. It is an emerging organic polymer material and is known as the "fifth largest plastic". It is widely used in many fields of the national economy because of its excellent performance. The product application fields involve light industry, chemical industry, electronics, textile, medical treatment, construction, building materials, automobile, national defense, aerospace and aviation, etc.

The Chinese patent with the publication number CN112608707A discloses a two-component polyurethane structural adhesive and its preparation method. The two-component polyurethane structural adhesive includes component A and component B. In parts by weight, the raw materials for the preparation of component A include The following components: 10-30 parts of castor oil polyol; 10-40 parts of phosphorus trichloride modified polyether polyol; 2-10 parts of aromatic polyester polyol; 15-40 parts of the first thermally conductive filler parts; 10 parts to 30 parts of the first flame retardant filler; 0 parts to 30 parts of the first auxiliary agent, in parts by weight, the raw materials for the preparation of component B include the following components: 5 parts of isocyanate-terminated polyurethane prepolymer 30 parts; 30-60 parts of polymethylene polyphenyl polyisocyanate; 15-40 parts of the second heat-conducting filler; 10-30 parts of the second flame-retardant filler; 0-6 parts of the second auxiliary agent. Because castor oil polyol has high ignition point, low freezing point and good thermal stability, which greatly improves the flame retardant performance of the material, phosphorus trichloride modified polyether polyol is a special alkyl phosphite stabilizer, and at the same time It is a phosphorus-containing polyol flame retardant, which has high thermal stability, weather resistance and hydrolysis resistance, and significantly enhances the flame retardant performance and shear strength of the material. Phosphorus trichloride modified polyether polyol is added to A The amount of flame-retardant fillers in the components can be reduced, the proportion of solid components in the components is reduced, and the proportion of liquid components is increased, thereby reducing the density of the components. Aromatic polyester polyols have excellent hydrolysis resistance, thermal stability and The characteristics of the primary hydroxyl group can significantly improve the adhesion of the glue to various metals and plastics under high temperature conditions, thereby improving the high temperature shear strength of the material. Phosphorus trichloride modified polyether polyol and isocyanate-terminated polyurethane The polymer components have a synergistic effect. After mixing component A and component B, phosphorus trichloride-modified polyether polyol can promote the occurrence of cross-linking reaction of isocyanate-terminated polyurethane prepolymer in the system and improve the reaction rate. Crosslinking density, there is a synergistic effect between the two, which significantly improves the shear strength and flame retardancy of the material. The two-component polyurethane structural adhesive of the present invention has low density, excellent flame retardancy and thermal conductivity, and high high temperature shear strength. shear strength and low temperature curing properties. However, the two-component polyurethane structural adhesive has poor adhesion to the PET film, and the peel strength between the two-component polyurethane structural adhesive and the PET film is less than 1N/mm, and there is a problem of easy degumming during use.

Therefore, it is necessary to develop a polyurethane structural adhesive and a preparation method thereof to avoid the above-mentioned problems existing in the prior art.

Contents of the invention

The purpose of the present invention is to provide a kind of polyurethane structural adhesive and preparation method thereof, solve the problem that polyurethane structural adhesive and PET film material are bonded, easy degumming problem in the process of use, simultaneously between polyurethane structural adhesive and PET film material The peel strength is greater than 1N/mm.

A polyurethane structural adhesive according to the present invention is used for bonding with PET film materials, including a first component and a second component;

The first component includes a prepolymer, a first thermally conductive filler, and a first tackifier;

The second component includes polyester polyol, a second thermally conductive filler and a second tackifier;

The prepolymer is composed of isocyanate and polycaprolactone polyol, the isocyanate is composed of HDI trimer and modified MDI, and the polyester polyol is composed of polycaprolactone polyol and modified castor oil, so The volume ratio of the first component to the second component is (0.9-1.1):(0.9-1.1).

The beneficial effects of the polyurethane structural adhesive of the present invention are: due to the small molecular weight and low polarity of the HDI trimer, it can infiltrate the PET film material, and the modified MDI has strong mechanical strength, low viscosity and good water resistance. Lactone polyol has low polarity, good toughness, and can infiltrate PET film materials. The prepolymer is composed of HDI trimer, modified MDI and polycaprolactone polyol, which makes the mechanical strength and water resistance of the prepolymer Better, and can better infiltrate PET film; polyester polyol is composed of polycaprolactone polyol and modified castor oil, which makes polyester polyol have better hydrophobicity, strength and toughness, and can also infiltrate PET Membrane material; the volume ratio of the first component to the second component is (0.9-1.1): (0.9-1.1), so that the first component and the second component are mixed evenly and the reaction is thorough; the Polyurethane structural adhesive is composed of prepolymer, first thermally conductive filler, first tackifier, polyester polyol, second thermally conductive filler and second tackifier, which makes polyurethane structural adhesive have better mechanical strength, water resistance and Toughness, can better infiltrate the PET film material, so that the peel strength between the polyurethane structural adhesive and the PET film material is greater than 1N/mm, which solves the problem of easy degumming in the process of use after the polyurethane structural adhesive is bonded to the PET film material The problem.

Optionally, the average molecular weight of the modified castor oil is 400-800, and the average functionality of the modified castor oil is 3.

Optionally, both the polycaprolactone polyol in the first component and the polycaprolactone polyol in the second component have a number average molecular weight of 300-1000.

Optionally, based on the mass percentage of the first component, the content of the HDI trimer is 10-20%, the content of the modified MDI is 18-30%, and the content of the first component The content of the polycaprolactone polyol is 20-30%, the content of the first heat-conducting filler is 35-50%, and the content of the first tackifier is 1-3%.

Optionally, based on the mass percentage of the second component, the content of the polycaprolactone polyol in the second component is 10-30%, and the content of the modified castor oil is 20-40%, the content of the second heat-conducting filler is 40-60%, and the content of the second tackifier is 1-3%.

Optionally, the first thermally conductive filler includes at least one of aluminum nitride, boron nitride, silicon nitride, aluminum oxide, magnesium oxide, and aluminum hydroxide, and the second thermally conductive filler includes aluminum nitride, nitrogen At least one of boron nitride, silicon nitride, aluminum oxide, magnesium oxide and aluminum hydroxide.

Optionally, both the first thermally conductive filler and the second thermally conductive filler are aluminum hydroxide.

Optionally, both the first tackifier and the second tackifier are fumed silica.

Another object of the present invention is to provide a preparation method of polyurethane structural adhesive, comprising the following steps:

Using HDI trimer and modified MDI for mixing to make isocyanate;

Using the isocyanate and polycaprolactone polyol to perform a temperature rise reaction to prepare a prepolymer;

mixing the prepolymer, the first thermally conductive filler and the first tackifier to prepare the first component;

Using polycaprolactone polyol and modified castor oil for mixing to make polyester polyol;

mixing the polyester polyol, a second thermally conductive filler and a second tackifier to prepare a second component;

The first component and the second component are used for a mixing reaction to prepare the polyurethane structural adhesive, and the volume ratio of the first component to the second component is (0.9-1.1) :(0.9～1.1).

The beneficial effects of the preparation method of the polyurethane structural adhesive of the present invention are: due to the small molecular weight and low polarity of the HDI trimer, it can infiltrate the PET film material, and the modified MDI has strong mechanical strength, low viscosity and good water resistance. , polycaprolactone polyol has low polarity, good toughness, and can infiltrate PET film materials. The prepolymer is composed of HDI trimer, modified MDI and polycaprolactone polyol, which makes the mechanical strength of the prepolymer It has better water resistance and can better infiltrate PET film materials; polyester polyol is composed of polycaprolactone polyol and modified castor oil, which makes polyester polyol have better hydrophobicity, strength and toughness, and also Can infiltrate the PET film material; the volume ratio of the first component to the second component is (0.9～1.1):(0.9～1.1), so that the first component and the second component are mixed evenly and the reaction is thorough ; The polyurethane structural adhesive is composed of a prepolymer, a first thermally conductive filler, a first tackifier, a polyester polyol, a second thermally conductive filler and a second tackifier, so that the polyurethane structural adhesive has better mechanical strength, Water resistance and toughness, can better infiltrate the PET film material, so that the peel strength between the polyurethane structural adhesive and the PET film material is greater than 1N/mm, which solves the problem of the polyurethane structural adhesive bonding with the PET film material. The problem of easy degumming.

Optionally, the temperature of the heating reaction is 70-100°C.

Description of drawings Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. the embodiment. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by those skilled in the art to which the present invention belongs. As used herein, "comprising" and similar words mean that the elements or items appearing before the word include the elements or items listed after the word and their equivalents, without excluding other elements or items.

In an embodiment of the present invention, a polyurethane structural adhesive is used for bonding with PET film materials, including a first component and a second component;

The first component includes a prepolymer, a first thermally conductive filler, and a first tackifier;

The second component includes polyester polyol, a second thermally conductive filler and a second tackifier;

The prepolymer is composed of isocyanate and polycaprolactone polyol, the isocyanate is composed of HDI trimer and modified MDI, and the polyester polyol is composed of polycaprolactone polyol and modified castor oil, so The volume ratio of the first component to the second component is (0.9-1.1):(0.9-1.1). Due to the small molecular weight and low polarity of HDI trimer, it can infiltrate PET film materials. The modified MDI has strong mechanical strength, low viscosity and good water resistance. Polycaprolactone polyol has low polarity and good toughness. And can infiltrate PET film, the prepolymer is composed of HDI trimer, modified MDI and polycaprolactone polyol, which makes the prepolymer have better mechanical strength and water resistance, and can better infiltrate PET film ; Polyester polyol is composed of polycaprolactone polyol and modified castor oil, so that polyester polyol has good hydrophobicity, strength and toughness, and can also infiltrate PET film; said first component and said The volume ratio of the second component is (0.9～1.1):(0.9～1.1), so that the first component and the second component are mixed evenly and the reaction is thorough; the polyurethane structural adhesive is composed of a prepolymer, a first thermally conductive filler , the first tackifier, polyester polyol, the second thermally conductive filler and the second tackifier, so that the polyurethane structural adhesive has better mechanical strength, water resistance and toughness, and can better infiltrate the PET film, so that The peeling strength between the polyurethane structural adhesive and the PET film material is greater than 1N/mm, and the problem of easy degumming in the process of use after the polyurethane structural adhesive is bonded to the PET film material is solved.

In some embodiments of the present invention, the HDI trimer is obtained by trimerization of hexamethylene diisocyanate under catalysis, HDI is hexamethylene diisocyanate, and its chemical formula is C ₈ H ₁₂ N ₂ O ₂ , CAS No. 822-06-0.

In some embodiments of the present invention, the modified MDI is carbodiimide-modified MDI, and the carbodiimide-modified MDI is liquefied MDI, also called monomer-modified MDI, which is pure MDI through Self-condensation reaction, in which carbodiimide group (-N=C=N-) is introduced, MDI is diphenylmethane-4,4'-diisocyanate, chemical formula is C ₁₅ H ₁₀ N ₂ O ₂ , CAS The number is 101-68-8.

In some embodiments of the present invention, the average molecular weight of the modified castor oil is 400-800, and the average functionality of the modified castor oil is 3.

In some embodiments of the present invention, the polycaprolactone polyol in the first component and the polycaprolactone polyol in the second component both have a number average molecular weight of 300-1000.

In some embodiments of the present invention, based on the mass percentage of the first component, the content of the HDI trimer is 10-20%, the content of the modified MDI is 18-30%, and the content of the modified MDI is 18-30%. The content of the polycaprolactone polyol in the first component is 20-30%, the content of the first heat-conducting filler is 35-50%, and the content of the first tackifier is 1-3%. .

In some embodiments of the present invention, based on the mass percentage of the second component, the content of the polycaprolactone polyol in the second component is 10-30%, and the modified castor The content of sesame oil is 20-40%, the content of the second heat-conducting filler is 40-60%, and the content of the second thickener is 1-3%.

In some embodiments of the present invention, the first thermally conductive filler includes at least one of aluminum nitride, boron nitride, silicon nitride, aluminum oxide, magnesium oxide, and aluminum hydroxide, and the second thermally conductive filler includes nitrogen at least one of aluminum oxide, boron nitride, silicon nitride, aluminum oxide, magnesium oxide, and aluminum hydroxide.

In some possible embodiments of the present invention, both the first thermally conductive filler and the second thermally conductive filler are aluminum hydroxide.

In some embodiments of the present invention, both the first tackifier and the second tackifier are fumed silica.

In an embodiment of the present invention, the preparation method of the polyurethane structural adhesive comprises the following steps:

Using HDI trimer and modified MDI for mixing to make isocyanate;

Using the isocyanate and polycaprolactone polyol to perform a temperature rise reaction to prepare a prepolymer;

mixing the prepolymer, the first thermally conductive filler and the first tackifier to prepare the first component;

Using polycaprolactone polyol and modified castor oil for mixing to make polyester polyol;

mixing the polyester polyol, a second thermally conductive filler and a second tackifier to prepare a second component;

The first component and the second component are used for a mixing reaction to prepare the polyurethane structural adhesive, and the volume ratio of the first component to the second component is (0.9-1.1) :(0.9～1.1). Due to the small molecular weight and low polarity of HDI trimer, it can infiltrate PET film materials. The modified MDI has strong mechanical strength, low viscosity and good water resistance. Polycaprolactone polyol has low polarity and good toughness. And can infiltrate PET film, the prepolymer is composed of HDI trimer, modified MDI and polycaprolactone polyol, which makes the prepolymer have better mechanical strength and water resistance, and can better infiltrate PET film ; Polyester polyol is composed of polycaprolactone polyol and modified castor oil, so that polyester polyol has good hydrophobicity, strength and toughness, and can also infiltrate PET film; said first component and said The volume ratio of the second component is (0.9～1.1):(0.9～1.1), so that the first component and the second component are mixed evenly and the reaction is thorough; the polyurethane structural adhesive is composed of a prepolymer, a first thermally conductive filler , the first tackifier, polyester polyol, the second thermally conductive filler and the second tackifier, so that the polyurethane structural adhesive has better mechanical strength, water resistance and toughness, and can better infiltrate the PET film, so that The peeling strength between the polyurethane structural adhesive and the PET film material is greater than 1N/mm, and the problem of easy degumming in the process of use after the polyurethane structural adhesive is bonded to the PET film material is solved.

In some possible embodiments of the present invention, the temperature of the heating reaction is 70-100°C.

In some other possible embodiments of the present invention, the isocyanate is weighed and placed in a container, and the polycaprolactone polyol is added while stirring under the condition of 70-100°C, and dry nitrogen is passed into the container Afterwards, prepolymerization is carried out to obtain a prepolymer, and when the content of the isocyanate reaches 5-20%, the prepolymerization discharge is stopped.

Example

Examples 1-6

Examples 1-6 of the present invention respectively provide a polyurethane structural adhesive, the specific components and contents of which are shown in Table 1.

Components and content of polyurethane structural adhesive in table 1 embodiment 1-6

The preparation method of embodiment 1-6 is:

Using HDI trimer and modified MDI for mixing to make isocyanate;

Weigh the isocyanate and place it in a container, add the polycaprolactone polyol while stirring under the condition of 70-100°C, and pre-polymerize after passing dry nitrogen into the container to obtain a pre-polymerized body, until the isocyanate content is 5 to 20%, stop the prepolymerization discharge.

mixing the prepolymer, the first thermally conductive filler and the first tackifier to prepare the first component;

Using polycaprolactone polyol and modified castor oil for mixing to make polyester polyol;

mixing the polyester polyol, a second thermally conductive filler and a second tackifier to prepare a second component;

Use the first component and the second component to carry out a mixing reaction to prepare the polyurethane structural adhesive, the volume ratio of the first component and the second component in Example 1 is 1:0.9 The volume ratio of the first component and the second component described in embodiment 2 is 1:1; the volume ratio of the first component and the second component described in embodiment 3 is 1:1.1 The volume ratio of the first component and the second component described in embodiment 4 is 0.9:1; the volume ratio of the first component and the second component described in embodiment 5 is 1:1 ; The volume ratio of the first component and the second component described in embodiment 6 is 1.1:1.

Performance Evaluation:

The polyurethane structural adhesive provided in the comparative example is produced by Debang Technology Materials Co., Ltd., and the product model is PU2117F.

The peel strength between the polyurethane structural adhesive in the embodiment 1-6 and the comparative example and the PET film is obtained according to the test method test in the GB/T 2791 standard, and the polyurethane structural adhesive in the embodiment 1-6 and the comparative example The tensile and shear strength is tested according to the test method in the ISO 4587 standard.

Table 2 Performance parameters of polyurethane structural adhesive

As can be seen from Table 2, the peel strength between the polyurethane structural adhesive in the present invention and the PET film material is all greater than 1N/mm, and the peel strength between the polyurethane structural adhesive and the PET film material in the comparative example is 0.8N/mm, The peel strength between the polyurethane structural adhesive and the PET film material in the present invention increases, thereby solving the problem that the polyurethane structural adhesive and the PET film material are easily degummed in the process of use; the tensile shear strength of the polyurethane structural adhesive in the present invention It is 7.3～8.0MPa, and the tensile-shear strength of the polyurethane structural adhesive in the comparative example is 7.6MPa, thus can know, while the peeling strength between the polyurethane structural adhesive of the present invention and PET film material increases, the performance of tensile-shear strength Unaffected, in line with market requirements for tensile and shear strength.

The foregoing examples are illustrative only, and are used to explain some features of the methods described in the present invention. The appended claims are intended to claim the broadest scope conceivable and the embodiments presented herein are merely illustrations of selected implementations according to all possible combinations of embodiments. Accordingly, it is the applicant's intention that the appended claims not be limited by the selection of examples which characterize the invention. Certain numerical ranges used in the claims also include sub-ranges therein, and changes within these ranges should also be construed as being covered by the appended claims where possible.

Claims (10)

1. A polyurethane structural adhesive, characterized in that it is used for bonding with PET film materials, including a first component and a second component;

   The first component includes a prepolymer, a first thermally conductive filler, and a first tackifier;

   The second component includes polyester polyol, a second thermally conductive filler and a second tackifier;

   The prepolymer is composed of isocyanate and polycaprolactone polyol, the isocyanate is composed of HDI trimer and modified MDI, and the polyester polyol is composed of polycaprolactone polyol and modified castor oil, so The volume ratio of the first component to the second component is (0.9-1.1):(0.9-1.1).
2. The polyurethane structural adhesive according to claim 1, characterized in that, the average molecular weight of the modified castor oil is 400-800, and the average functionality of the modified castor oil is 3.
3. The polyurethane structural adhesive according to claim 1, wherein the number average of the polycaprolactone polyol in the first component and the polycaprolactone polyol in the second component is The molecular weights are all 300-1000.
4. The polyurethane structural adhesive according to claim 1, characterized in that, based on the mass percentage of the first component, the content of the HDI trimer is 10% to 20%, and the content of the modified MDI is 18-30%, the content of the polycaprolactone polyol in the first component is 20-30%, the content of the first thermally conductive filler is 35-50%, the first tackifier The content is 1 to 3%.
5. The polyurethane structural adhesive according to claim 1, characterized in that, based on the mass percentage of the second component, the content of the polycaprolactone polyol in the second component is 10 to 30 %, the content of the modified castor oil is 20-40%, the content of the second heat-conducting filler is 40-60%, and the content of the second thickener is 1-3%.
6. The polyurethane structural adhesive according to claim 1, wherein the first thermally conductive filler comprises at least one of aluminum nitride, boron nitride, silicon nitride, aluminum oxide, magnesium oxide and aluminum hydroxide, so The second thermally conductive filler includes at least one of aluminum nitride, boron nitride, silicon nitride, aluminum oxide, magnesium oxide and aluminum hydroxide.
7. The polyurethane structural adhesive according to claim 1 or 7, characterized in that, both the first thermally conductive filler and the second thermally conductive filler are aluminum hydroxide.
8. The polyurethane structural adhesive according to claim 1, wherein both the first tackifier and the second tackifier are fumed silica.
9. A preparation method of polyurethane structural adhesive, is characterized in that, comprises the following steps:

   Using HDI trimer and modified MDI for mixing to make isocyanate;

   Using the isocyanate and polycaprolactone polyol to perform a temperature rise reaction to prepare a prepolymer;

   mixing the prepolymer, the first thermally conductive filler and the first tackifier to prepare the first component;

   Using polycaprolactone polyol and modified castor oil for mixing to make polyester polyol;

   mixing the polyester polyol, a second thermally conductive filler and a second tackifier to prepare a second component;

   The first component and the second component are used for a mixing reaction to prepare the polyurethane structural adhesive, and the volume ratio of the first component to the second component is (0.9-1.1) :(0.9～1.1).
10. The preparation method of polyurethane structural adhesive according to claim 9, characterized in that, the temperature of the heating reaction is 70-100°C.