Modified melamino-formaldehyde resin mold cleaning material as well as preparation method and application thereof

Abstract

The invention discloses a modified melamino-formaldehyde resin mold cleaning material as well as a preparation method and application thereof. The modified melamino-formaldehyde resin mold cleaning material is prepared from the following raw materials in parts by weight: 30 to 180 parts of matrix resin, 1 to 5 parts of modifier, 0.1 to 0.5 part of catalyst, 5 to 15 parts of flexibilizer, 5 to 15 parts of filler and 1 to 3 parts of release agent. The modifier comprises at least one of benzene-substituted melamine, polyvinyl alcohol, polyethylene glycol, polyhedral oligomeric silsesquioxane, tris (2-hydroxyethyl) isocyanurate or polyether amine D-230, by introducing the modifier, the brittleness of the melamine formaldehyde resin can be reduced, the demolding performance can be improved, and good cleaning performance, demolding performance and filling performance can be achieved; the problem of breakage during demolding is solved, the situation of poor filling almost does not occur, and the cleaning performance is excellent.

Description

Technical Field

[0001] The present invention relates to the field of polymer compounds obtained by reactions other than carbon-carbon unsaturated bonds, and in particular to a modified melamine formaldehyde resin mold cleaning material, a preparation method and an application thereof. Background Art

[0002] As electronic products evolve towards greater sophistication and miniaturization, companies are promoting large-scale packaging technology, enabling the integration of more chips within a single package and improving product performance. After multiple cycles of packaging, mold surfaces retain residual plastic encapsulation material, release agents, and other contaminants, impacting package precision and product quality. Traditional melamine-formaldehyde resins are used to clean molds, but they are brittle and prone to breaking and cracking during demolding, becoming lodged in mold crevices, leading to demolding failure and even mold damage. Therefore, developing a mold cleaning material that combines both cleaning properties and flexibility is crucial.

[0003] Chinese invention patent application CN119036705A discloses a mold cleaning sponge and mold cleaning composition for semiconductor packaging molds, as well as methods for using the composition. By adjusting the melamine sponge's formulation and foaming process, the sponge's curing degree is effectively controlled. Compared to common melamine sponges on the market, the sponge possesses more reactive groups (hydroxyl / amino groups), effectively improving mold cleaning effectiveness through interfacial reactions. However, the sponge exhibits high brittleness and easily breaks during demolding. Chinese invention patent application CN118725228A discloses a melamine sponge and its preparation method. By optimizing the sponge's ingredients and preparation process, a curing agent and catalyst are added during the foaming process, significantly improving the product's performance. The sponge exhibits high strength, low density, and high elasticity, but suffers from mold release difficulties. Summary of the Invention

[0004] In order to develop a mold cleaning material with both cleaning function and flexibility, the first aspect of the present invention provides a modified melamine formaldehyde resin mold cleaning material, the raw materials for preparation include, by weight, 30-180 parts of main resin, 1-5 parts of modifier, 0.1-0.5 parts of catalyst, 5-15 parts of toughening agent, 5-15 parts of filler, and 1-3 parts of release agent; The modifier includes at least one of phenylguanamine, polyvinyl alcohol, polyethylene glycol, cage-type polysilsesquioxane, tris(2-hydroxyethyl)isocyanurate or polyetheramine.

[0005] The polyetheramine is polyetheramine D-230.

[0006] As an embodiment, the main resin includes melamine and formaldehyde, and the molar ratio of melamine to formaldehyde is 1:(1-8).

[0007] As an embodiment, the main resin includes melamine and formaldehyde, and the molar ratio of melamine to formaldehyde is 1:(1.5-5).

[0008] As an embodiment, the main resin includes melamine and formaldehyde, and the molar ratio of melamine to formaldehyde is 1:1.5 or 1:5.

[0009] As an embodiment, the catalyst includes an organic acid or an organic anhydride, wherein the organic acid or an organic anhydride includes a low melting point catalyst with a melting point of <90°C, and the organic acid or anhydride also includes a high melting point catalyst with a melting point of 90°C ≤ ≤ 300°C.

[0010] As an embodiment, the weight ratio of the low melting point catalyst to the high melting point catalyst is (1-150):1.

[0011] As an embodiment, the weight ratio of the low melting point catalyst to the high melting point catalyst is (2-10):1.

[0012] As an embodiment, the weight ratio of the low melting point catalyst to the high melting point catalyst is 2:1.

[0013] As an embodiment, the low melting point catalyst includes at least one of lauric acid, 3-phenylpropionic acid, maleic anhydride, cis-9-tetradecenoic acid or stearic acid; the high melting point catalyst includes at least one of m-toluic acid, o-toluic acid, benzoic acid, succinic anhydride, naphthalenesulfonic acid, adipic acid, terephthalic acid or phthalic anhydride.

[0014] As an embodiment, the low melting point catalyst includes stearic acid.

[0015] As an embodiment, the high melting point catalyst includes at least one of o-toluic acid or benzoic acid.

[0016] In one embodiment, the filler comprises silica, and the silica comprises at least one of spherical silica and angular silica.

[0017] As an embodiment, the average particle size of the silicon dioxide is 1-50 μm.

[0018] As an embodiment, the average particle size of the spherical silica is 10-30 μm; the average particle size of the angular silica is 30-50 μm.

[0019] As an embodiment, the average particle size of the spherical silica is 20 μm; the average particle size of the angular silica is 50 μm.

[0020] As an embodiment, the toughening agent includes cellulose, and the length of the cellulose is 50-300 μm.

[0021] As an embodiment, the length of the cellulose is 100 μm.

[0022] In the present invention, cellulose with a length of 100 μm is mixed with a resin prepolymer through wet blending, and the hydroxyl groups on the cellulose surface form hydrogen bonds with the resin premix to achieve modification of the melamine formaldehyde resin, thereby improving the flexibility of the mold clearing material and reducing breakage during the mold clearing process.

[0023] As an embodiment, the release agent includes at least one of polypropylene wax, polyethylene wax, oxidized polyethylene wax, amide wax or montan wax.

[0024] A second aspect of the present invention provides a method for preparing a modified melamine formaldehyde resin mold cleaning material, comprising the following steps: S1: The main resins are mixed and polycondensed under alkaline conditions. After the reaction is completed, a modifier is added and stirred for 10-30 minutes to obtain a resin prepolymer; S2: Add toughening agent to the resin prepolymer, continue stirring and mixing until uniform, and dry to obtain a mixed material; S3: crush the mixed material, sieve it, add filler, release agent and catalyst, and mix them evenly; S4: Prepare into a rubber cake and mold it into shape.

[0025] As an embodiment, the temperature of the polycondensation reaction in step S1 is 60-80° C., and the time of the polycondensation reaction is 1-3 hours.

[0026] As an embodiment, the temperature of the polycondensation reaction in step S1 is 70° C., and the time of the polycondensation reaction is 2 hours.

[0027] As an embodiment, the pH of the alkaline condition in step S1 is 8-9.

[0028] As an embodiment, the pH of the alkaline condition in step S1 is 8.5.

[0029] As an embodiment, the alkaline condition in step S1 is adjusted by using a 10 wt % sodium hydroxide aqueous solution.

[0030] As an embodiment, the mesh size of the sieving in step S3 is 50-70 meshes.

[0031] As an embodiment, the mesh size of the sieving in step S3 is 60 meshes.

[0032] As an embodiment, the curing temperature in step S4 is 150-190° C., the curing pressure is 30-80 MPa, and the curing time is 30-120 s.

[0033] The third aspect of the present invention provides an application of a modified melamine formaldehyde resin mold cleaning material for cleaning molds of semiconductor packaging materials.

[0034] Compared with the prior art, the present invention has the following beneficial effects: (1) The modified melamine formaldehyde resin mold removal material of the present invention can reduce the brittleness of the melamine formaldehyde resin and improve the demoulding performance by introducing a modifier of phenyl cyanamide, polyvinyl alcohol, polyethylene glycol, cage polysilsesquioxane, tris (2-hydroxyethyl) isocyanurate or polyetheramine into the melamine formaldehyde resin.

[0035] (2) The modified melamine formaldehyde resin mold cleaning material of the present invention can shorten the gel time of the melamine formaldehyde resin mold cleaning material and improve production efficiency by adopting a combination of a high melting point catalyst and a low melting point catalyst.

[0036] (3) The modified melamine formaldehyde resin mold cleaning material of the present invention introduces cellulose with a length of 100 μm as a toughening agent, which can further improve the flexibility of the modified melamine formaldehyde resin mold cleaning material and improve the cleaning effect.

[0037] (4) The modified melamine formaldehyde resin mold cleaning material of the present invention uses two different average particle sizes of 50 μm and 120 μm and different shapes of silica as fillers, which can optimize the spiral flow length effect and improve the filling and cleaning effect of the packaging mold of fine products.

[0038] (5) The modified melamine formaldehyde resin mold cleaning material of the present invention has good cleaning performance, demoulding performance and filling performance, improves the problem of breakage during demoulding, almost no poor filling occurs, and has excellent cleaning performance. DETAILED DESCRIPTION

[0039] Examples and Comparative Examples A modified melamine formaldehyde resin mold cleaning material, the raw materials for preparation include main resin, modifier, catalyst, toughening agent, filler, and release agent in parts by weight; melamine and formaldehyde are measured in a molar ratio, see Table 1-2 below.

[0040] Table 1

[0041] Table 2

[0042] The benzoguanamine was purchased from Foshan Wengkaier, brand name cymel 659.

[0043] The polyvinyl alcohol was purchased from Aladdin, with the brand name P139545; the polyethylene glycol was purchased from Aladdin, with the brand name P103728; the polyetheramine D-230 was purchased from Aladdin, with the brand name P108071; and the cage-type polysilsesquioxane was purchased from Aladdin, with the brand name O404818.

[0044] The cellulose fiber has a length of 100 μm, is brand TM150, and is a functional reinforcing fiber purchased from Wuxi Lvjian Technology Co., Ltd.

[0045] The average particle size of the spherical silica is 20 μm, which is purchased from Jiangsu Lianrui New Material Technology Co., Ltd.; the average particle size of the angular silica is 50 μm, which is purchased from Jiangsu Lianrui New Material Technology Co., Ltd.

[0046] The polyethylene wax was purchased from Clariant, with the brand names Licowax PE 130 and Licowax PE 510. A method for preparing a modified melamine formaldehyde resin mold cleaning material comprises the following steps: S1: The main resins are mixed and polycondensed under alkaline conditions. After the reaction is completed, a modifier is added and stirred for 20 minutes to obtain a resin prepolymer; S2: Add toughening agent to the resin prepolymer, continue stirring and mixing until uniform, and dry to obtain a mixed material; S3: crush the mixed material, sieve it, add filler, release agent and catalyst, and mix them evenly; S4: Prepare into a rubber cake and mold it into shape.

[0047] The temperature of the polycondensation reaction in step S1 is 70° C., and the time of the polycondensation reaction is 2 hours.

[0048] The pH of the alkaline condition in step S1 is 8.5. The alkaline condition in step S1 is adjusted by using a 10 wt % sodium hydroxide aqueous solution.

[0049] The mesh size of the sieving in step S3 is 60 meshes.

[0050] In step S4, the curing temperature is 180° C., the curing pressure is 75 MPa, and the curing time is 120 seconds.

[0051] Performance Testing 1. Gel time: obtained by referring to the national standard GB / T 40564-2021.

[0052] 2.Spiral flow length: Tested according to GB / T 40564-2021.

[0053] 3. Demolding performance: After cleaning with the mold cleaning materials prepared in the examples and comparative examples, the amount of residual resin in the mold cavity during demolding was <2%, which was considered excellent; 2-5%, which was considered good; and >5%, which was considered poor.

[0054] 4. Cleaning performance: After cleaning with the mold cleaning materials prepared in the examples and comparative examples, the visual stain residue was judged to be excellent if it was less than 5%, good if it was 5-20%, and poor if it was greater than 20%.

[0055] The specific test results are shown in Table 3.

[0056] Table 3

[0057] Examples 3, 4, 5, and 9, incorporating a modifier in an appropriate weight ratio with the melamine-formaldehyde resin, exhibited excellent mold release and cleaning performance, with suitable gel times and spiral flow lengths. Examples 1, 2, 6, 7, and 8 exhibited a poor combination of the modifier and melamine-formaldehyde resin, resulting in slightly reduced cleaning and mold release performance. Comparative Examples 1 and 2, in which no modifier was introduced, exhibited poor mold release performance and were prone to breakage during demolding.

Claims

1. A modified melamine formaldehyde resin mold cleaning material, characterized in that: The raw materials prepared by weight include 30-180 parts of main resin, 1-5 parts of modifier, 0.1-0.5 parts of catalyst, 5-15 parts of toughening agent, 5-15 parts of filler, and 1-3 parts of release agent; The modifier includes at least one of phenylguanamine, polyvinyl alcohol, polyethylene glycol, cage-type polysilsesquioxane, tris(2-hydroxyethyl)isocyanurate or polyetheramine.

2. The modified melamine formaldehyde resin mold cleaning material according to claim 1, characterized in that: The main resin includes melamine and formaldehyde, and the molar ratio of the melamine to the formaldehyde is 1:(1-8).

3. The modified melamine formaldehyde resin mold cleaning material according to claim 1, characterized in that: The catalyst includes an organic acid or an organic acid anhydride, wherein the organic acid or an organic acid anhydride includes a low melting point catalyst with a melting point less than 90°C, and the organic acid or an organic acid anhydride also includes a high melting point catalyst with a melting point of 90°C≤300°C.

4. The modified melamine formaldehyde resin mold cleaning material according to claim 3, characterized in that: The weight ratio of the low melting point catalyst to the high melting point catalyst is (1-150):

1.

5. The modified melamine formaldehyde resin mold cleaning material according to claim 3, characterized in that: The low melting point catalyst includes at least one of lauric acid, 3-phenylpropionic acid, maleic anhydride, cis-9-tetradecenoic acid or stearic acid; the high melting point catalyst includes at least one of m-toluic acid, o-toluic acid, benzoic acid, succinic anhydride, naphthalenesulfonic acid, adipic acid, terephthalic acid or phthalic anhydride.

6. The modified melamine formaldehyde resin mold cleaning material according to claim 1, characterized in that: The filler includes silica, and the silica includes at least one of spherical silica or angular silica.

7. The modified melamine formaldehyde resin mold cleaning material according to claim 6, characterized in that: The average particle size of the silicon dioxide is 1-50 μm.

8. The modified melamine formaldehyde resin mold cleaning material according to claim 6, characterized in that: The toughening agent includes cellulose, and the length of the cellulose is 50-300 μm.

9. A method for preparing the modified melamine formaldehyde resin mold cleaning material according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: Mix the main resins and carry out polycondensation reaction under alkaline conditions. After the reaction is completed, add the modifier and continue stirring for 10-30 minutes; S2: Add toughening agent, continue stirring and mixing evenly, and dry to obtain a mixed material; S3: crush the mixed material, sieve it, add filler, release agent and catalyst, and mix them evenly; S4: Prepare into a rubber cake and mold it into shape.

10. An application of the modified melamine formaldehyde resin mold cleaning material according to any one of claims 1 to 8, characterized in that: Used in cleaning molds of semiconductor packaging materials.

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