Preparation method of phenolic resin with excellent curability and phenolic resin molding compound

Abstract

The present invention belongs to the technical field of phenolic resin molding compounds, and particularly relates to a preparation method of a phenolic resin with excellent curability and a phenolic resin molding compound. A preparation method of a phenolic resin with excellent curability includes the following steps: mixing a phenolic component and glyoxal evenly at a molar ratio of 1:(0.5-0.7), adding a weak acid salt catalyst of a divalent metal ion, a weak acid catalyst, and hexadecyl diphenyl ether disulfonate, reacting at 60-80 °C for 1-2 h, adding polyvinyl butyral, heating to boiling and refluxing for 3-5 h, and after the reaction is completed, distilling off water and free phenol; the phenolic component is composed of phenol, 4-nonylphenol, bisphenol F, anacardic acid, and coniferyl alcohol mixed at a molar ratio of 1:(0.2-0.3):(0.1-0.15):(0.06-0.08):(0.08-0.14). The phenolic resin of the present application has excellent curability and a low free phenol content.

Description

Technical Field

[0001] The present invention belongs to the technical field of phenolic resin molding compounds, and particularly relates to a preparation method of a phenolic resin with excellent curability and a phenolic resin molding compound. Background Art

[0002] Phenolic resin molding compounds have excellent heat resistance, electrical properties, mechanical properties, dimensional stability, etc. In addition, due to the low cost, they are widely used in the fields of household appliances, electrical accessories, and mechanical accessories. According to the cross-linking and curing process of phenolic resin, phenolic molding compounds are divided into one-step products that do not require a curing agent and two-step products that must add a curing agent. The one-step process does not require the addition of a curing agent, but has problems such as complex process, difficult quality control, and environmental pollution. Compared with the one-step method, the two-step process has simple technology, less process pollution, low production cost, stable product quality, and long storage period.

[0003] Phenolic molding compounds mainly use phenolic resin as an adhesive. The phenolic resin obtained by the addition and appropriate polycondensation reaction of phenol and aldehyde in a synthesis reaction device is usually a mixed system of linear (branched) oligomers with low molecular weight and various hydroxymethylphenols. The curing of phenolic resin is a process of cross-linking the linear (branched) structure into a network structure and transforming it into a network structure. The curability of phenolic resin has a great influence on the curability of phenolic resin molding compounds. The patent with the authorization announcement number CN 1066473 C provides a phenolic resin molding compound with high fluidity, high thermal stability, and excellent high-temperature curability in the molten state. Specifically, hexamethylenetetramine is used as a curing agent, and a high-oortho phenolic varnish type phenolic resin with a number average molecular weight of 350 - 500 and an ortho bond / para bond ratio of 1.5 - 2.5 is used, which improves the activation energy of the resin and improves the curability of the resin in the mold.

[0004] During the research process, the applicant found that the above-mentioned high-oortho phenolic varnish type phenolic resin with a number average molecular weight of 350 - 500 and an ortho bond / para bond ratio of (1.5 - 2.5):1 has a high free phenol content due to unreacted phenolic hydroxyl groups inside. Hexamethylenetetramine is used as a curing agent, which has certain toxicity, and there is still a certain amount of free phenol after the phenolic resin is cured. Summary of the Invention

[0005] In order to improve the curability of phenolic resin while reducing the free phenol content of phenolic resin, the present application provides a preparation method of a phenolic resin with excellent curability and a phenolic resin molding compound.

[0006] In the first aspect, the present application provides a preparation method of a phenolic resin with excellent curability, which is realized by adopting the following technical scheme:

[0007] A preparation method of a phenolic resin with excellent curability includes the following steps:

[0008] Mix the phenolic component and glyoxal evenly at a molar ratio of 1:(0.5 - 0.7), add a weak acid salt catalyst of divalent metal ions, a weak acid catalyst, and hexadecyl diphenyl ether disulfonate, heat up to 60 - 80 °C and react for 1 - 2 h, add polyvinyl butyral, continue heating to boiling and reflux for 3 - 5 h. After the reaction is completed, distill off water and free phenol;

[0009] The phenolic component is composed of phenol, 4-nonylphenol, bisphenol F, anacardic acid, and coniferyl alcohol mixed at a molar ratio of 1:(0.2 - 0.3):(0.1 - 0.15):(0.06 - 0.08):(0.08 - 0.14);

[0010] The mass ratio of the weak acid salt catalyst of divalent metal ions, the weak acid catalyst, hexadecyl diphenyl ether disulfonate, polyvinyl butyral, and the phenolic component is (0.4 - 0.6):(0.2 - 0.3):(5 - 8):(10 - 15):100.

[0011] By adopting the above technical solution, since the para positions of 4-nonylphenol, bisphenol F, and coniferyl alcohol are substituted, 4-nonylphenol and bisphenol F can increase the ortho bond / para bond ratio of phenolic resin, making the ortho bond / para bond ratio higher than 1.5:1, improving the curability of phenolic resin and shortening the molding time of phenolic molding compound; although one ortho position of anacardic acid is substituted, the steric hindrance of -C 15 H 31-2n is relatively large, restricting the addition reaction of glyoxal with the para position of anacardic acid, further increasing the ortho bond / para bond ratio of phenolic resin, and the carboxyl group in the anacardic acid molecule reacts with the hydroxymethyl group in the phenolic resin molecule, which can reduce the free phenol content in the phenolic resin. By controlling the molar ratio of phenol, 4-nonylphenol, bisphenol F, anacardic acid, and coniferyl alcohol within 1:(0.2 - 0.3):(0.1 - 0.15):(0.06 - 0.08):(0.08 - 0.14) in this application, the activation energy of the resin is significantly increased, thereby improving the curability of phenolic resin.

[0012] The weak acid salt catalyst of divalent metal ions contains divalent metal ions Me 2+ selected during the synthesis process with ortho - guiding function, which can highlight the difference in the degree of electrophilic substitution of hydroxyl groups at the ortho and para positions on the ring of the phenolic component, enabling glyoxal to preferentially undergo an addition reaction with the ortho position of the phenolic component, thereby increasing the ortho bond / para bond ratio of phenolic resin.

[0013] The hexadecyl diphenyl ether disulfonate molecule contains a long carbon chain, two benzene rings, ether oxygen atoms, and sulfonic acid groups, which can improve the dispersibility and stability of phenolic resin, enabling the hexadecyl diphenyl ether disulfonate to be evenly dispersed in the phenolic resin. Moreover, the hexadecyl diphenyl ether disulfonate has a strong adsorption capacity and can adsorb free phenol to a certain extent. The hydroxyl groups in the polyvinyl butyral molecule react with the hydroxymethyl groups in the phenolic resin molecule to form a graft copolymer. Additionally, the hydroxyl groups in polyvinyl butyral react with the hydroxyl groups on coniferyl alcohol, improving the toughness of the phenolic resin and reducing the content of free phenol in the phenolic resin. During the research process, the applicant also unexpectedly found that the combined action of hexadecyl diphenyl ether disulfonate and polyvinyl butyral not only results in a lower content of free phenol in the phenolic resin but also improves the stability of the cross-linked structure of the phenolic resin, and resin can be produced even when the ortho-bond / para-bond ratio of the phenolic resin is higher than 2.5:1.

[0014] Preferably, the phenolic component is composed of phenol, 4-nonylphenol, bisphenol F, anacardic acid, and coniferyl alcohol mixed in a molar ratio of 1:0.25:0.1:0.08:0.12.

[0015] When the molar ratio of phenol, 4-nonylphenol, bisphenol F, anacardic acid, and coniferyl alcohol in the phenolic substance is 1:0.25:0.1:0.08:0.12, the curability of the phenolic resin obtained by the reaction of the phenolic substance with glyoxal is relatively good.

[0016] Preferably, the molar ratio of the phenolic component to glyoxal is 1:0.55.

[0017] Preferably, the mass ratio of the weak acid salt catalyst of divalent metal ions, weak acid catalyst, hexadecyl diphenyl ether disulfonate, polyvinyl butyral, and phenolic component is 0.5:0.25:8:12:100.

[0018] When the mass ratio of the weak acid salt catalyst of divalent metal ions, weak acid catalyst, hexadecyl diphenyl ether disulfonate, polyvinyl butyral, and phenolic component is 0.5:0.25:8:12:100, the content of free phenol in the phenolic resin obtained by the reaction of the phenolic substance with glyoxal is relatively low, and the curability is relatively good.

[0019] Preferably, the weak acid catalyst is composed of 2,2-dimethylolpropionic acid, acetic acid, and succinic acid mixed in a mass ratio of (0.2 - 0.3):1:(0.5 - 0.7).

[0020] The weak acid catalyst compounded by 2,2-dimethylolpropionic acid, acetic acid and succinic acid can not only adjust the pH of the phenolic resin preparation, improve the polymerization rate of the phenolic resin, but also reduce the free phenol content of the phenolic resin. This is because the hydroxymethyl in 2,2-dimethylolpropionic acid and the extra carboxyl groups in succinic acid react with the free phenol in the phenolic resin, significantly reducing the free phenol content.

[0021] Preferably, the weak acid salt catalyst of the divalent metal ion is composed of magnesium acetate and zinc acetate mixed in a mass ratio of 1:(0.6-0.8).

[0022] The weak acid salt catalyst of the divalent metal ion is obtained by compounding two components, magnesium acetate and zinc acetate. By adjusting the ratio of the two components, the ortho-guiding effect of the weak acid salt catalyst of the divalent metal ion can be fully exerted, and phenolic resin with a longer molecular chain can be formed. At the same time, magnesium acetate and zinc acetate cooperate with the filler, making the filler more evenly distributed in the cross-linked network structure of the phenolic resin, improving the compatibility between the phenolic resin and the filler.

[0023] In the second aspect, the present application provides a phenolic resin with excellent curability, which is realized by the following technical solution:

[0024] A phenolic resin with excellent curability is prepared by the above preparation method.

[0025] The phenolic resin with excellent curability prepared in the present application has a low free phenol content and excellent curability.

[0026] In the third aspect, the present application provides a phenolic resin molding compound, which is realized by the following technical solution:

[0027] A phenolic resin molding compound, by weight, its preparation raw materials include: 30-40 parts of the above phenolic resin with excellent curability, 3-5 parts of a curing agent, 20-30 parts of a filler, 3-5 parts of polyethylene and 0.8-1.2 parts of a mold release agent;

[0028] The curing agent is composed of hydroxymethylurea and propylene glycol carbonate mixed in a mass ratio of 1:(0.7-0.9).

[0029] The curing agent compounded by hydroxymethylurea and propylene glycol carbonate is basically non-toxic. Hydroxymethylurea has a high branching reaction point. Hydroxymethylurea, propylene glycol carbonate and polyvinyl butyral cooperate with each other, which can improve the activity of the hydroxymethyl in the phenolic resin molecule, improve the curing speed, and make the curability of the phenolic resin better.

[0030] Preferably, the phenolic resin molding compound further includes 1-3 parts by weight of zinc oxide.

[0031] Preferably, the filler is a mixture of montmorillonite, kaolin and lignocellulose in a mass ratio of 1:(0.7-0.9):(2-3).

[0032] In summary, this application has the following beneficial effects:

[0033] 1. The present application adopts 4-nonylphenol, bisphenol F, anacardic acid and coniferyl alcohol to replace part of phenol, thereby improving the ortho-bond / para-bond ratio of the phenolic resin, improving the curability of the phenolic resin, and reducing the free phenol content in the phenolic resin.

[0034] 2. The present application adopts hexadecyl diphenyl ether disulfonate and polyvinyl butyral to reduce the free phenol content in the phenolic resin.

[0035] 3. The present application adopts a weak acid catalyst composed of 2,2-dihydroxymethylpropionic acid, acetic acid and succinic acid, which significantly reduces the free phenol content.

[0036] 4. The present application adopts a curing agent compounded from hydroxymethyl urea and propylene glycol carbonate, which is substantially non-toxic and has a good curing effect on phenolic resin. DETAILED DESCRIPTION

[0037] The present application is further described in detail below with reference to the embodiments.

[0038] Example

[0039] Embodiments 1-16 provide a phenolic resin with excellent curability, and the following description is made using Embodiment 1 as an example.

[0040] The phenolic resin with excellent curability provided in Example 1 is prepared by the following steps:

[0041] 941 g (10 mol) of phenol, 441 g (2 mol) of 4-nonylphenol, 200 g (1 mol) of bisphenol F, 208 g (0.6 mol) of anacardic acid and 144 g (0.8 mol) of coniferyl alcohol were mixed to obtain a phenol component;

[0042] 418 g (7.2 mol) of glyoxal was added to the above phenolic component, mixed, and stirred evenly, then 7.7 g of zinc acetate, 3.9 g of acetic acid, and 97 g of sodium hexadecyl diphenyl ether disulfonate were added, stirred evenly, heated to 60° C. and reacted at 60° C. for 2 h. After the reaction, 193 g of polyvinyl butyral was added, stirred evenly, and then heated to boiling and refluxed for 5 h. After the reaction was completed, the water was removed by distillation at 100° C. for 3 h, and the free phenol was removed by heating to 200° C. and vacuum distillation was continued for 2 h (negative pressure 0.97 MPa). The vacuum discharge was closed to obtain a phenolic resin with excellent curability.

[0043] Example 2-15 is different from Example 1 only in that the amounts of each preparation raw material are different, as shown in Table 1 specifically.

[0044] Table 1 Amounts of each preparation raw material in Examples 1-15

[0045]

[0046]

[0047]

[0048] Example 16 is different from Example 12 only in that the first heating temperature is 80 °C and the reaction is carried out at 80 °C for 1 h, and the reflux reaction is 3 h.

[0049] Comparative Example

[0050] Comparative Examples 1-6 are different from Example 1 only in that the amounts of each preparation raw material are different, as shown in Table 2 specifically.

[0051] Table 2 Amounts of each preparation raw material in Comparative Examples 1-6

[0052]

[0053]

[0054] Application Example

[0055] Application Examples 1-18 provide phenolic resin molding compounds, and the following takes Application Example 1 as an example for illustration.

[0056] The preparation steps of the phenolic resin molding compound provided by Application Example 1 are as follows:

[0057] S1. Mix 1.5 kg of phenolic resin with excellent curability, 0.15 kg of curing agent, 1 kg of filler, 0.15 kg of polyethylene, 0.04 kg of zinc stearate and 0.05 kg of zinc oxide, and pulverize to obtain a mixed material raw powder;

[0058] S2. Plasticize the above-mentioned mixed material raw powder at 110 °C, extrude and press into sheets, cool and pulverize to obtain finished product particles of the molding compound;

[0059] S3. Inject and mold the above-mentioned finished product particles of the molding compound to obtain a phenolic resin molding compound;

[0060] Among them, the phenolic resin with excellent curability is derived from Example 1;

[0061] The curing agent is composed of hydroxymethylurea and propylene glycol carbonate mixed in a mass ratio of 1:0.7;

[0062] The filler is composed of montmorillonite, kaolin and wood cellulose, which are mixed in a mass ratio of 1:0.7:2.

[0063] Applied Example 2-16 is different from Applied Example 1 only in that: the source of the phenolic resin with excellent curability is different, as shown in Table 3 specifically.

[0064] Table 3 Sources of phenolic resins with excellent curability in Applied Examples 1-16

[0065]

[0066]

[0067] Applied Example 17 is different from Applied Example 12 only in that: the curing agent is composed of hydroxymethylurea and propylene glycol carbonate, which are mixed in a mass ratio of 1:0.8.

[0068] Applied Example 18 is different from Applied Example 17 only in that: the filler is composed of montmorillonite, kaolin and wood cellulose, which are mixed in a mass ratio of 1:0.9:3.

[0069] Comparative Applied Examples

[0070] Comparative Applied Examples 1-6 are different from Applied Example 1 only in that: the source of the phenolic resin with excellent curability is different, as shown in Table 4 specifically.

[0071] Table 4 Sources of phenolic resins with excellent curability in Comparative Applied Examples 1-6

[0072]

[0073] Comparative Applied Example 7 is different from Applied Example 1 only in that: the curing agent is hydroxymethylurea.

[0074] Comparative Applied Example 8 is different from Applied Example 1 only in that: the curing agent is propylene glycol carbonate.

[0075] Comparative Applied Example 9 is different from Applied Example 1 only in that: the curing agent is hexamethylenetetramine.

[0076] Performance Detection Test

[0077] 1. For the phenolic resins prepared in Examples 1-16 and Comparative Examples 1-6 of the present application, the free phenol content of the phenolic resins was detected.

[0078] Free phenol content: The content of free phenol in the phenolic resin was detected according to the detection method in HG / T2621-1994 "Standard for Determining the Residual Phenol Content in Phenolic Resin by Gas Chromatography", and the detection results are shown in Table 5.

[0079] Table 5 Detection Results of Free Phenol Content

[0080]

[0081]

[0082] 2. For the phenolic resin molding compounds prepared in Application Examples 1-18 and Comparative Application Examples 1-9 of this application, curability testing was carried out.

[0083] Curability: By changing the time that the molded test piece remains in the mold, check for the appearance of foaming on the surface of the test piece, and record this time to represent curability. The shorter the time, the better the curability. The test results are shown in Table 6.

[0084] Table 6 Curability Test Results

[0085]

[0086]

[0087] The following details this application in view of the test data in Table 5 and Table 6.

[0088] From the test data of Example 1 and Comparative Example 1 (Application Example 1 and Comparative Application Example 1), it can be seen that the partial replacement of phenol with 4-nonylphenol can improve the curability of phenolic resin.

[0089] From the test data of Example 1 and Comparative Example 2 (Application Example 1 and Comparative Application Example 2), it can be seen that the partial replacement of phenol with bisphenol F can improve the curability of phenolic resin.

[0090] From the test data of Example 1 and Comparative Example 3 (Application Example 1 and Comparative Application Example 3), it can be seen that the partial replacement of phenol with anacardic acid, and the carboxyl group of anacardic acid can react with the hydroxymethyl group in the phenolic resin molecule, which can reduce the free phenol content in the phenolic resin and at the same time improve the curability of the phenolic resin.

[0091] From the test data of Example 1 and Comparative Example 4 (Application Example 1 and Comparative Application Example 5), it can be seen that the partial replacement of phenol with coniferyl alcohol can improve the curability of phenolic resin and at the same time reduce the free phenol content in the phenolic resin.

[0092] From the test data of Example 1 and Comparative Examples 5-6 (Application Example 1 and Comparative Application Examples 5-6), it can be seen that the combined action of hexadecyl diphenyl ether disulfonate and polyvinyl butyral significantly reduces the free phenol content in the phenolic resin and has relatively good curability.

[0093] From the test data of Application Example 1 and Comparative Application Examples 7-8, it can be seen that the curing agent compounded with hydroxymethylurea and propylene glycol carbonate significantly improves the curability of phenolic resin.

[0094] From the test data of Application Example 1 and Comparative Application Example 9, it can be seen that the curing agent compounded with hydroxymethylurea and propylene carbonate is not only non-toxic, but also the curing property of the phenolic resin is not lower than that of hexamethylenetetramine for the phenolic resin, and is even higher than that of hexamethylenetetramine.

[0095] From the test data of Examples 1-3, it can be seen that in Example 3, the molar ratio of phenol, 4-nonylphenol, bisphenol F, anacardic acid, and coniferyl alcohol in the phenolic substances is 1:0.25:0.1:0.08:0.12, and the curability of the phenolic resin obtained by the reaction of the phenolic substances with glyoxal is relatively excellent.

[0096] From the test data of Examples 5-7, it can be seen that in Example 7, the mass ratio of the weak acid salt catalyst of divalent metal ions, weak acid catalyst, hexadecyl diphenyl ether disulfonate, polyvinyl butyral, and phenolic components is 0.5:0.25:8:12:100, and the free phenol content of the phenolic resin obtained by the reaction of the phenolic substances with glyoxal is relatively low, and the curability is relatively excellent.

[0097] From the test data of Examples 7-10, it can be seen that the weak acid salt catalyst of divalent metal ions compounded with magnesium acetate and zinc acetate improves the curability of the phenolic resin.

[0098] From the test data of Examples 9, 11-15, it can be seen that the weak acid catalyst compounded with 2,2-dimethylolpropionic acid, acetic acid, and succinic acid has good catalytic effect. Since the hydroxymethyl group in 2,2-dimethylolpropionic acid and the excess carboxyl group in succinic acid react with the free phenol in the phenolic resin, the free phenol content is significantly reduced.

[0099] This specific embodiment is only an explanation of the present application, and it does not limit the present application. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A preparation method of a phenolic resin with excellent curability, characterized in that, It includes the following steps: Mix the phenolic component and glyoxal evenly at a molar ratio of 1:(0.5 - 0.7), add the weak acid salt catalyst of divalent metal ions, weak acid catalyst, hexadecyl diphenyl ether disulfonate, heat up to 60 - 80 °C and react for 1 - 2 h, add polyvinyl butyral, continue to heat to boiling and reflux for 3 - 5 h. After the reaction is completed, distill off the water and free phenol; The phenolic component is composed of phenol, 4-nonylphenol, bisphenol F, anacardic acid, and coniferyl alcohol mixed at a molar ratio of 1:(0.2 - 0.3):(0.1 - 0.15):(0.06 - 0.08):(0.08 - 0.14); The mass ratio of the weak acid salt catalyst of divalent metal ions, weak acid catalyst, hexadecyl diphenyl ether disulfonate, polyvinyl butyral, and phenolic component is (0.4 - 0.6):(0.2 - 0.3):(5 - 8):(10 - 15):

100.

2. The preparation method of a phenolic resin with excellent curability according to claim 1, characterized in that, The phenolic component is composed of phenol, 4-nonylphenol, bisphenol F, anacardic acid, and coniferyl alcohol mixed at a molar ratio of 1:0.25:0.1:0.08:0.

12.

3. The preparation method of a phenolic resin with excellent curability according to claim 2, characterized in that, The molar ratio of the phenolic component and glyoxal is 1:0.

55.

4. The preparation method of a phenolic resin with excellent curability according to claim 2, characterized in that, The mass ratio of the weak acid salt catalyst of divalent metal ions, weak acid catalyst, hexadecyl diphenyl ether disulfonate, polyvinyl butyral, and phenolic component is 0.5:0.25:8:12:

100.

5. The preparation method of a phenolic resin with excellent curability according to claim 1, characterized in that, The weak acid catalyst is composed of 2,2-dimethylolpropionic acid, acetic acid, and succinic acid mixed at a mass ratio of (0.2 - 0.3):1:(0.5 - 0.7).

6. The preparation method of a phenolic resin with excellent curability according to claim 1, characterized in that, The weak acid salt catalyst of divalent metal ions is composed of magnesium acetate and zinc acetate mixed at a mass ratio of 1:(0.6 - 0.8).

7. A phenolic resin with excellent curability prepared by the preparation method according to any one of claims 1 - 6.

8. A phenolic resin molding compound, characterized in that, By weight, its preparation raw materials include: 30 - 40 parts of the phenolic resin with excellent curability according to claim 7, 3 - 5 parts of curing agent, 20 - 30 parts of filler, 3 - 5 parts of polyethylene, and 0.8 - 1.2 parts of release agent; The curing agent is composed of methylolurea and propylene glycol carbonate mixed at a mass ratio of 1:(0.7 - 0.9).

9. The phenolic resin molding compound according to claim 8, wherein, The phenolic resin molding compound also includes 1 - 3 parts by weight of zinc oxide.

10. The phenolic resin molding compound according to claim 8, wherein, The filler is composed of montmorillonite, kaolin, and wood cellulose mixed at a mass ratio of 1:(0.7 - 0.9):(2 - 3).

Images