Preparation method of side hydrogen polysiloxane modified novolac epoxy resin and coating

Abstract

The invention provides side hydrogen polysiloxane modified novolac epoxy resin and a preparation method of a coating. The side hydrogen polysiloxane modified novolac epoxy resin comprises the following components in parts by weight: 100 parts of novolac epoxy resin; 5 to 35 parts of side hydrogen polysiloxane; 0.01 to 1 part of a catalyst; 50 to 200 parts of a solvent; and 5-50 parts of a reactive diluent. The novolac epoxy resin, the side hydrogen polysiloxane and the solvent are added into a container in proportion, then the container with the mixture is placed into a heater, the mixture can be stirred in advance or in the heater, the catalyst is added into the container while the temperature is increased, the catalyst is slowly dropwise added, the dropwise adding is completed within 10-40 min, the temperature is increased to 60-90 DEG C, and the mixture is cooled to room temperature; and keeping the temperature for 4-24 hours to react. The preparation method has the beneficial effects that the brittleness problem of the coating can be improved and the flexibility of the coating can be improved by utilizing the flexible characteristic of the siloxane chain segment; the side hydrogen polysiloxane modified novolac epoxy resin with uniform morphology is obtained by controlling the preparation process and the material proportion.

Description

Technical Field

[0001] The invention belongs to the field of epoxy resin coatings, and in particular relates to a preparation method of a side hydrogen polysiloxane modified phenolic epoxy resin and a coating. Background Art

[0002] Polysiloxane has excellent heat resistance and moisture resistance. The bond energy of Si-O constituting the main chain of polysiloxane polymer macromolecule chain is 372KJ / mol. Therefore, polysiloxane polymer is more stable than general organic polymer in heat and oxygen environment, and exhibits excellent physical and mechanical properties at high and low temperatures (-60℃~+250℃). If the excellent performance of polysiloxane is extended to phenolic resin, a good coating will be obtained.

[0003] However, there are few research papers on polysiloxane-modified phenolic resins. The main reason is that the improvement of polymer performance by polysiloxane is mainly reflected in improving heat resistance and mechanical properties. However, phenolic resin itself contains high-density benzene rings, and its heat resistance is relatively high in polymers, so there is not much room for improvement. In addition, phenolic resin has poor toughness due to its high-density benzene rings. The resin prepared by the usual method will be very brittle, which is easy to cause cracking during use and difficult to form a film. In order to prepare reliable polysiloxane-modified phenolic resins, we need to improve the existing preparation method, while further improving the heat resistance of phenolic resins, giving the coating a certain flexibility. Summary of the invention

[0004] In view of this, the present invention aims to provide a preparation method of a side hydrogen polysiloxane modified phenolic epoxy resin and a coating.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] A side hydrogen polysiloxane modified phenolic epoxy resin comprises 100 parts by weight of phenolic epoxy resin, 5 to 35 parts by weight of side hydrogen polysiloxane, 0.01 to 1 part of a catalyst, and 50 to 200 parts of a solvent.

[0007] Furthermore, it also includes 5 to 50 parts of active diluent.

[0008] Furthermore, the relative molecular mass of the phenolic epoxy resin is between 1000 and 5000;

[0009] The relative molecular mass of the pendant hydrogen siloxane is between 500 and 4000, and the pendant hydrogen content (mass percentage) is between 0.05% and 3%.

[0010] Further, the catalyst is one or more of: H2PtCl6·6H2O (chloroplatinic acid hexahydrate), (Ph3P)4Pd, (Ph3P)2PdCl2, (PhCN)2PdCl2, [RhCl(CO)2]2;

[0011] The solvent is one or more of methyl formate, acetone, ether, dichloromethane, benzene, toluene, xylene, and trimethylbenzene;

[0012] The active diluent is one or more of 1,6-hexanediol diacrylate (HDDA), 1,6-hexanediol dimethacrylate (HDDMA), diethylene glycol diacrylate (DEGDA) and neopentyl glycol diethoxy / propoxy diacrylate.

[0013] A method for preparing a side hydrogen polysiloxane modified phenolic epoxy resin comprises the following steps: adding the phenolic epoxy resin, side hydrogen polysiloxane and a solvent into a container in proportion, placing the container (three-necked flask) with the mixture into a heater (oil bath or water bath), stirring the mixture in advance or in the heater, adding a catalyst into the container while heating the mixture, slowly dripping the catalyst, and completing the dripping within 10-40 minutes, heating the mixture to 60-90° C., and keeping the temperature for 4-24 hours to allow the mixture to react;

[0014] After the reaction is completed, the mixed solution in the container is poured into a separatory funnel and allowed to stand for 1-5 hours, and the lower layer of viscous liquid is taken out to obtain a side hydrogen polysiloxane modified phenolic epoxy resin.

[0015] Furthermore, adding a reactive diluent to the side hydrogen polysiloxane modified phenolic epoxy resin prepared in claim 5 can reduce the viscosity.

[0016] A method for preparing a side hydrogen polysiloxane modified phenolic epoxy resin coating, comprising mixing the side hydrogen polysiloxane modified phenolic epoxy resin prepared in claim 6 with a peroxide curing agent and an amine curing agent, and curing the mixture at a temperature of 60-200° C. for 6-48 hours to obtain a side hydrogen polysiloxane modified phenolic epoxy coating.

[0017] Further, the specific steps are as follows:

[0018] S1, mixing the side hydrogen polysiloxane modified phenolic epoxy resin and the amine curing agent at room temperature for later use;

[0019] S2, slowly drip the peroxide curing agent into the mixed solution of S1, and then stir at room temperature for 10-60 minutes;

[0020] S3, under stirring conditions, spray the mixed solution obtained in S2 on the surface of the object (stainless steel plate), heat to 60-200°C and cure for 6-48h to form a coating.

[0021] Furthermore, the peroxide curing agent is one or more of dibenzoyl peroxide, cyclohexanone peroxide, dihydropropane peroxide, and tert-butyl hydroperoxide;

[0022] The amine curing agent is one or more of diethylenetriamine, triethylenetetramine, polyethylenepolyamine, meta-xylylenediamine, T-31 curing agent, 591 curing agent, 593 curing agent, triethanolamine, benzyldimethylamine, methylbenzyldimethylamine, DMP-10, and DMP-30.

[0023] Furthermore, the weight ratio of the side hydrogen polysiloxane modified phenolic epoxy resin to the peroxide curing agent is 100:2-20;

[0024] The weight ratio of the side hydrogen polysiloxane modified phenolic epoxy resin to the amine curing agent is 100:1-15.

[0025] The advantages and positive effects of the present invention are:

[0026] 1. The present invention adopts side hydrogen polysiloxane modification to obtain a block-like polymer, and utilizes the flexibility of the siloxane segment to improve the brittleness of the coating and enhance the flexibility of the coating;

[0027] 2. Since the compatibility of polysiloxane and epoxy resin is poor, the polymer generated by the reaction between the two is easy to separate into phases. The present invention obtains a side hydrogen polysiloxane-modified phenolic epoxy resin with uniform morphology by controlling the preparation process and the ratio of the two.

[0028] 3. In order to increase the curing rate of the side hydrogen polysiloxane modified phenolic epoxy resin, the present invention adds a reactive diluent and uses peroxide and diamine as a mixed curing agent to obtain a coating with an adjustable curing rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 It is the structural formula of the side hydrogen polysiloxane modified phenolic epoxy resin;

[0031] Figure 2 This is a comparison chart of infrared spectra of common phenolic epoxy resin and side hydrogen polysiloxane modified phenolic epoxy resin;

[0032] Figure 3It is a comparison chart of mechanical properties of side hydrogen polysiloxane modified phenolic epoxy resin coatings containing different mass fractions of side hydrogen polysiloxane;

[0033] Figure 4 This is a comparison chart of thermal properties between common phenolic epoxy resin and side hydrogen polysiloxane modified phenolic epoxy resin coating containing different mass fractions of side hydrogen polysiloxane;

[0034] Figure 5 It is the SEM picture of the common phenolic epoxy resin and the side hydrogen polysiloxane modified phenolic epoxy resin coating containing different mass fractions of side hydrogen polysiloxane;

[0035] Figure 6 This is a comparison chart of the contact angles of ordinary phenolic epoxy resin and side hydrogen polysiloxane-modified phenolic epoxy resin coatings containing different mass fractions of side hydrogen polysiloxane. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] Figure 1 , Figure 5 They are the structural formula and SEM image of the side hydrogen polysiloxane modified phenolic epoxy resin.

[0039] Figure 2 This is the infrared spectrum of ordinary phenolic epoxy resin and side hydrogen polysiloxane modified phenolic epoxy resin. It can be seen that their spectra are different, and the side hydrogen polysiloxane modified phenolic epoxy resin has a higher absorbance.

[0040] Example 1

[0041] 100 parts of phenolic epoxy resin with a relative molecular mass of 1000, 10 parts of pendant hydrogen polysiloxane with a pendant hydrogen content of 1.6% (weight percentage) and 100 parts of benzene are placed in a three-necked flask, stirred evenly, put into an oil bath pot and slowly heated, 0.04 parts of hexahydrate chloroplatinic acid catalyst (H2PtCl6·6H2O) are slowly added dropwise, the addition is completed within 10-40 minutes, and the reaction is carried out at 60°C for 24 hours;

[0042] The obtained mixed solution was poured into a separatory funnel and allowed to stand for 2 hours. The lower layer of viscous liquid was taken out, 40 parts of 1,6-hexanediol diacrylate (HDDA) active diluent was added, and stirred at room temperature for 30 minutes to mix well, thereby obtaining a side hydrogen polysiloxane-modified phenolic epoxy resin (b), wherein the mass fraction of the side hydrogen polysiloxane in the resin was 5%, and the parts of the catalyst and the active diluent were not considered.

[0043] After mixing 100 parts of the prepared side hydrogen polysiloxane modified phenolic epoxy resin (b) and 5 parts of T-31 curing agent at room temperature, 8 parts of dihydrogen peroxide are added under stirring conditions, and stirred at room temperature for 30 minutes; sprayed on a stainless steel plate, heated to 120°C and cured for 40 hours to obtain a side hydrogen polysiloxane modified phenolic epoxy resin coating (b).

[0044] Example 2

[0045] 100 parts of phenolic epoxy resin with a relative molecular mass of 2000, 20 parts of 1.6% lateral hydrogen polysiloxane and 100 parts of p-xylene are placed in a three-necked flask, stirred evenly, put into an oil bath and slowly heated, and 0.02 parts of hexahydrate chloroplatinic acid (H2PtCl6·6H2O) catalyst is slowly added dropwise, and the mixture is dripped within 20 minutes, and reacted at 70°C for 24 hours;

[0046] The obtained mixed solution was poured into a separating funnel and allowed to stand for 4 hours. The lower layer of viscous liquid was taken out, and 30 parts of 1,6-hexanediol diacrylate (HDDA) active diluent were added, and stirred at room temperature for 20 minutes to obtain a side hydrogen polysiloxane modified phenolic epoxy resin (c). The mass fraction of side hydrogen polysiloxane in the resin was 10% (the fraction of catalyst and active diluent was not considered).

[0047] After mixing 100 parts of the prepared side hydrogen polysiloxane modified phenolic epoxy resin 1 and 5 parts of triethylenetetramine at room temperature, 5 parts of dibenzoyl peroxide were added and stirred at room temperature for 30 minutes; the temperature was raised to 100° C. and cured for 24 hours to obtain a side hydrogen polysiloxane modified phenolic epoxy resin coating (c).

[0048] Example 3

[0049] 100 parts of phenolic epoxy resin with a relative molecular mass of 3000, 30 parts of 1.6% side hydrogen polysiloxane and 100 parts of acetone were placed in a three-necked flask, stirred evenly, put into an oil bath and slowly heated, and 0.05 parts of chloroplatinic acid catalyst was dripped in within 40 minutes, and reacted at 70°C for 24 hours;

[0050] The obtained mixed solution was poured into a separating funnel and allowed to stand for 5 hours, the lower layer of viscous liquid was taken out, 50 parts of neopentyl glycol diethoxy / propoxy diacrylate active diluent were added, and stirred at room temperature for 20 minutes to obtain a side hydrogen polysiloxane modified phenolic epoxy resin (d). The mass fraction of side hydrogen polysiloxane in the resin was 15% (the fraction of catalyst and active diluent was not considered).

[0051] After mixing 100 parts of the prepared side hydrogen polysiloxane modified phenolic epoxy resin (d) and 3 parts of T-31 curing agent at room temperature, 5 parts of cyclohexanone peroxide were added and stirred at room temperature for 30 minutes; the temperature was raised to 80°C and cured for 30 hours to obtain a side hydrogen polysiloxane modified phenolic epoxy resin coating (d).

[0052] Example 4

[0053] 100 parts of phenolic epoxy resin with a relative molecular mass of 3000, 30 parts of 0.8% side hydrogen polysiloxane and 50 parts of p-xylene were placed in a three-necked flask, stirred evenly, put into an oil bath and slowly heated, and 0.02 parts of chloroplatinic acid catalyst was dripped in within 20 minutes, and reacted at 70°C for 18 hours.

[0054] The obtained mixed solution was poured into a separating funnel and allowed to stand for 2 hours, the lower layer of viscous liquid was taken out, 30 parts of neopentyl glycol diethoxy / propoxy diacrylate active diluent were added, and stirred at room temperature for 20 minutes to obtain a side hydrogen polysiloxane modified phenolic epoxy resin (e). The mass fraction of the side hydrogen polysiloxane in the resin was 20% (the fraction of the catalyst and the active diluent was not considered).

[0055] After 100 parts of the prepared side hydrogen polysiloxane modified phenolic epoxy resin (e) and 8 parts of triethylenetetramine are mixed at room temperature, 5 parts of dibenzoyl peroxide are added, and stirred at room temperature for 20 minutes; sprayed on a stainless steel plate, heated to 100°C and cured for 24 hours to obtain a side hydrogen polysiloxane modified phenolic epoxy resin coating (e).

[0056] Comparative Example 1

[0057] 100 parts of phenolic epoxy resin and 6 parts of T-31 curing agent were mixed at room temperature, stirred at room temperature for 30 minutes, sprayed on a stainless steel plate, and cured at a high temperature of about 80° C. for 30 hours to obtain a common phenolic epoxy resin coating (a).

[0058] Table 1 and Figure 3-Figure 6(a) represents the case of ordinary phenolic epoxy resin coating; (b) represents the case of phenolic epoxy resin coating modified by side hydrogen polysiloxane containing 5% by mass of side hydrogen polysiloxane; (c) represents the case of phenolic epoxy resin coating modified by side hydrogen polysiloxane containing 10% by mass of side hydrogen polysiloxane; (d) represents the case of phenolic epoxy resin coating modified by side hydrogen polysiloxane containing 15% by mass of side hydrogen polysiloxane; (e) represents the case of phenolic epoxy resin coating modified by side hydrogen polysiloxane containing 20% ​​by mass of side hydrogen polysiloxane;

[0059] The resin coatings obtained in Examples 1-4 and Comparative Example 1 are compared.

[0060] 1. Hardness comparison

[0061] As shown in Table 1, the hardness of the resin coating is about 90, which meets the use requirements.

[0062]

[0063] Table 1 Comparison of hardness of common phenolic epoxy resin and side hydrogen polysiloxane modified phenolic epoxy resin coating containing different mass fractions of side hydrogen polysiloxane

[0064] 2. Comparison of mechanical properties

[0065] pass Figure 3 It can be seen that different types of side hydrogen polysiloxane modified phenolic epoxy resin coatings can withstand a certain stress and have high flexibility. Ordinary phenolic epoxy resin cured products are too brittle to measure mechanical properties.

[0066] 3. Thermal performance comparison

[0067] pass Figure 4 From the comparison of thermal properties, it can be seen that in the high temperature range above 400°C, the performance of the side hydrogen polysiloxane modified phenolic epoxy resin coating in resisting thermal weight loss is better than that of the ordinary phenolic epoxy resin coating, and the higher the content of side hydrogen polysiloxane, the better the performance.

[0068] 4. Contact angle (cntact angle) comparison

[0069] pass Figure 6 It can be seen that the contact angle of the side hydrogen polysiloxane modified phenolic epoxy resin coating is greater than that of the ordinary phenolic epoxy resin coating. The higher the content of the side hydrogen polysiloxane, the larger the contact angle, the better the hydrophobicity, and the more waterproof.

[0070] The present invention firstly obtains a siloxane-modified phenolic epoxy resin matrix by a siloxane-hydrogenated polysiloxane and a double bond of a phenolic epoxy resin, then adds a reactive diluent to reduce the resin viscosity, and finally adds a peroxide curing agent for curing to prepare an epoxy coating. The polysiloxane modification can react the reactive polysiloxane with the phenolic epoxy through functional groups to form a siloxane / phenolic epoxy polymer, and a uniform phase is formed by adjusting the ratio and segment structure, thereby further improving the heat resistance of the phenolic resin and giving the coating a certain degree of flexibility. Compared with the prior art, the T of the resin synthesized by the siloxane-hydrogenated polysiloxane in the present invention is improved. 5％ The thermal stability is improved from 240℃ of the original resin to 268℃ when the content of side hydrogen polysiloxane is 5%. The tensile strength of the modified resin can still reach more than 10MPa, and the elongation at break is increased to more than 4%. The coating before modification breaks at the touch and cannot be measured. The toughness is improved and it will not break brittlely at room temperature.

[0071] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A side hydrogen polysiloxane modified phenolic epoxy resin, characterized in that: The invention comprises 100 parts by weight of phenolic epoxy resin, 5 to 35 parts by weight of side hydrogen polysiloxane, 0.01 to 1 part by weight of catalyst, and 50 to 200 parts by weight of solvent.

2. The side hydrogen polysiloxane modified phenolic epoxy resin according to claim 1, characterized in that: It also includes 5 to 50 parts of active diluent.

3. The side hydrogen polysiloxane modified phenolic epoxy resin according to claim 1, characterized in that: The relative molecular weight of the phenolic epoxy resin is between 1000 and 5000; The relative molecular mass of the pendant hydrogen siloxane is between 500 and 4000, and the pendant hydrogen content is between 0.05% and 3%.

4. The side hydrogen polysiloxane modified phenolic epoxy resin according to claim 2, characterized in that: The catalyst is one or more of H2PtCl6·6H2O, (Ph3P)4Pd, (Ph3P)2PdCl2, (PhCN)2PdCl2, [RhCl(CO)2]2; The solvent is one or more of methyl formate, acetone, ether, dichloromethane, benzene, toluene, xylene, and trimethylbenzene; The active diluent is one or more of 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate and neopentyl glycol diethoxy / propoxy diacrylate.

5. The method for preparing the side hydrogen polysiloxane modified phenolic epoxy resin according to claim 1, characterized in that: The phenolic epoxy resin, the side hydrogen polysiloxane and the solvent are added into a container in proportion, and the container with the mixture is placed in a heater, and a catalyst is added into the container while the temperature is raised to 60-90° C., and the temperature is kept for 4-24 hours to allow the reaction; After the reaction is completed, the mixed solution in the container is allowed to stand, and the lower layer of viscous liquid is taken out to obtain the side hydrogen polysiloxane modified phenolic epoxy resin.

6. The method for preparing the side hydrogen polysiloxane modified phenolic epoxy resin according to claim 5, characterized in that: Adding a reactive diluent to the side hydrogen polysiloxane modified phenolic epoxy resin prepared in claim 5 can reduce the viscosity.

7. A method for preparing a side hydrogen polysiloxane modified phenolic epoxy resin coating, characterized in that: The side hydrogen polysiloxane modified phenolic epoxy resin prepared in claim 6 is mixed with a peroxide curing agent and an amine curing agent, and cured at a temperature of 60-200° C. to obtain a side hydrogen polysiloxane modified phenolic epoxy coating.

8. The method for preparing the side hydrogen polysiloxane modified phenolic epoxy resin coating according to claim 7, characterized in that: The specific steps are as follows: S1, mixing the side hydrogen polysiloxane modified phenolic epoxy resin and the amine curing agent at room temperature for later use; S2, slowly drip the peroxide curing agent into the mixed solution of S1, and then stir at room temperature for 10-60 minutes; S3, applying the mixed solution obtained in S2 to the surface of the object, heating to 60-200° C. and curing for 6-48 hours to obtain a coating.

9. The method for preparing the side hydrogen polysiloxane modified phenolic epoxy resin coating according to claim 7 or 8, characterized in that: The peroxide curing agent is one or more of dibenzoyl peroxide, cyclohexanone peroxide, dihydropropane peroxide, and tert-butyl hydroperoxide; The amine curing agent is one or more of diethylenetriamine, triethylenetetramine, polyethylenepolyamine, meta-xylylenediamine, T-31 curing agent, 591 curing agent, 593 curing agent, triethanolamine, benzyldimethylamine, methylbenzyldimethylamine, DMP-10, and DMP-30.

10. The method for preparing the side hydrogen polysiloxane modified phenolic epoxy resin coating according to claim 7 or 8, characterized in that: The weight ratio of the side hydrogen polysiloxane modified phenolic epoxy resin to the peroxide curing agent is 100:2-20; The weight ratio of the side hydrogen polysiloxane modified phenolic epoxy resin to the amine curing agent is 100:1-15.

Images