CN109049790A - A kind of gum dipping process method improving water-soluble resin honeycomb core material compressive strength - Google Patents
A kind of gum dipping process method improving water-soluble resin honeycomb core material compressive strength Download PDFInfo
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- CN109049790A CN109049790A CN201810809189.7A CN201810809189A CN109049790A CN 109049790 A CN109049790 A CN 109049790A CN 201810809189 A CN201810809189 A CN 201810809189A CN 109049790 A CN109049790 A CN 109049790A
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- resin
- core material
- honeycomb core
- water
- compressive strength
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D99/00—Subject matter not provided for in other groups of this subclass
- B29D99/0089—Producing honeycomb structures
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B15/00—Pretreatment of the material to be shaped, not covered by groups B29B7/00 - B29B13/00
- B29B15/08—Pretreatment of the material to be shaped, not covered by groups B29B7/00 - B29B13/00 of reinforcements or fillers
- B29B15/10—Coating or impregnating independently of the moulding or shaping step
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Laminated Bodies (AREA)
Abstract
The invention belongs to technical field of composite material manufacturing, are related to a kind of gum dipping process method for improving water-soluble resin honeycomb core material compressive strength, which can be used for the preparation of aramid fiber paper honeycomb core material, improve the compressive strength of honeycomb core material.Impregnating resin is changed to water soluble phenol resin by the present invention, reduce the pollution that solvent volatilizees to environment, simultaneously because the free phenol content of water soluble phenol resin is far below traditional alcohol-soluble phenolic resin, harm of the free phenol to operator in immersing glue process is decreased.The present invention utilizes the characteristics of water soluble phenol resin itself in immersing glue process, using special gum dipping process method, effective control has been carried out to distribution situation of the resin on honeycomb wall, rubber column gel column is formed after so that resin is concentrated on honeycomb core material hexagon angle nearby, effectively raise the compressive strength of honeycomb core material, with compared with isodensity aramid paper honeycomb core material, its stable type compressive strength can be made to improve 30% or more using honeycomb core material prepared by the method for the invention.
Description
Technical field
The invention belongs to technical field of composite material manufacturing, are related to a kind of raising water-soluble resin honeycomb core material compressive strength
Gum dipping process method, which can be used for the preparation of aramid fiber paper honeycomb core material, improves the compressive strength of honeycomb core material.
Background technique
Aramid fiber paper honeycomb has obtained extensively because of specific strength height, the big and excellent electrical property of specific stiffness in aerospace field
Application, traditional aramid fiber paper honeycomb using alcohol-soluble phenolic resin carry out impregnation, the solvent evaporation rate of this resinoid is fast, resin
Distributed controll difficulty is big, therefore does not control the distribution of impregnating resin after impregnation, and resin is made more to be evenly distributed in bee
On nest wall, this resin distribution is unfavorable for improving the compressive strength of honeycomb core material.Aramid fiber paper honeycomb is in aircraft interior trim, rail traffic
Using relatively broad on interior trim and the non-bearing part of racing boat, these secondary bearing members are only more quick to the compression performance of honeycomb core material
Sense, and clearly required to cutting performance and tensile property are typically no.
Summary of the invention
The purpose of the present invention is being directed to the actual demand, the compressive strength with isodensity aramid paper honeycomb core material is improved
It is proposed a kind of gum dipping process method for improving water-soluble resin honeycomb core material compressive strength.
The technical scheme is that
Successively carry out impregnating resin preparation, impregnation, impregnating resin distributed controll, 4 step processing steps of water removal:
(1) impregnating resin configures: water soluble phenol resin being added in glue groove, then according to the ratio of 1:1 into glue groove
Aqueous solvent is added, water soluble phenol resin and aqueous solvent are measured into impregnating resin viscosity, impregnating resin viscosity model after mixing
Enclosing is 5cP~60cP, and temperature range is 23 ± 5 DEG C；
(2) impregnation: non-impregnation honeycomb block is put into impregnating resin, with the promotion speed of 10mm/min~200mm/min
Honeycomb block is lifted out impregnating resin liquid level；
(3) impregnating resin distributed controll: after honeycomb block is lifted out impregnating resin liquid level, 90 ° or 270 ° are overturn, by bee
Socket bore lattice are horizontally arranged 30min~300min,
(4) it removes water: honeycomb core material after impregnation being carried out except water process at high temperature, temperature for removing water is 40 DEG C~100 DEG C, is removed
The water time is 15min~60min；
(5) measurement honeycomb block density meet design requirements repetition step (2) to (4) until reaching design requirement density and is
Only.
In step (1), the water soluble phenol resin is mid-temperature-cure resin, solidification temperature≤160 DEG C, water-soluble >=
600%, free phenol content≤5%.
In step (1), impregnating resin range of viscosities is 10cP~40cP.
In step (2), promoting velocity interval is 40mm/min~160mm/min.
In step (5), when each impregnation, the difference between cellular density lifting capacity is no more than ± 3kg/m3。
In step (5), when repeating impregnation, the direction of improvement tune of rear soaking honeycomb block and preceding soaking honeycomb block
Turn 180 °.
In step (3), the honeycomb cell horizontal positioned time is 45min~120min.
In step (4), cellular temperature for removing water is 60 DEG C~90 DEG C after impregnation, and baking oven is warming up to tree after the completion of water removal
Initial reaction temperature precuring 5min~30min of rouge, then carry out second of dipping.
The solid content of the water soluble phenol resin original gelatin is 50%~75%.
The present invention have the advantage that and the utility model has the advantages that
(1) present invention is big for solvent usage in traditional aramid fiber paper honeycomb immersing glue process, and environment easy to pollute simultaneously deposits human body
The shortcomings that centainly endangering, impregnating resin is changed to water soluble phenol resin, reduces the pollution that solvent volatilizees to environment, together
When be far below traditional alcohol-soluble phenolic resin because of the free phenol content of water soluble phenol resin, decrease in immersing glue process and dissociate
Harm of the phenol to operator.
(2) present invention utilizes the characteristics of water soluble phenol resin itself in immersing glue process, using special gum dipping process
Method has carried out effective control to distribution situation of the resin on honeycomb wall, so that resin is concentrated on honeycomb core material hexagon angle attached
Rubber column gel column is formed after close, effectively raises the compressive strength of honeycomb core material, with compared with isodensity aramid paper honeycomb core material, is used
The honeycomb core material of the method for the invention preparation can make its stable type compressive strength improve 30% or more.
(3) preparing sandwich structure composite material using honeycomb core material made by gum dipping process of the present invention can effectively reduce
Construction weight, reduces material cost and manufacturing cost, further opens up honeycomb core material in the application in the fields such as high-speed rail, racing boat.
Detailed description of the invention
Fig. 1 is the gum dipping process flow chart for improving water-soluble resin honeycomb core material compressive strength.
Fig. 2 is honeycomb core material resin rubber column gel column situation schematic diagram.
Specific embodiment
Impregnating resin preparation, impregnation, impregnating resin distributed controll, water removal 4 are successively passed through by non-impregnation aramid paper honeycomb block
Step process processing, improves the compressive strength with isodensity aramid paper honeycomb core material.Specifically impregnation is carried out by following process:
(1) impregnating resin configures: water soluble phenol resin being added in glue groove, then according to the ratio of 1:1 into glue groove
Aqueous solvent is added, water soluble phenol resin and aqueous solvent are measured into impregnating resin viscosity, impregnating resin viscosity model after mixing
Enclosing is 5cP~60cP, and temperature range is 23 ± 5 DEG C.
(2) impregnation: non-impregnation honeycomb block is put into impregnating resin, with the promotion speed of 10mm/min~200mm/min
Honeycomb block is lifted out impregnating resin liquid level.When the close non-impregnation honeycomb block density of target density, can will promote speed is reduced
To 10mm/min or less.
(3) impregnating resin distributed controll: after honeycomb block is lifted out impregnating resin liquid level, 90 ° or 270 ° are overturn, by bee
Socket bore lattice are horizontally arranged 30min~300min, and the effect using impregnating resin surface tension and gravity makes it predominantly stay in six
On the shape honeycomb corner of side.
(4) it removes water: honeycomb core material after impregnation being carried out except water process at high temperature, temperature for removing water is 40 DEG C~100 DEG C, is removed
The water time is 15min~60min；
(5) when measurement honeycomb block density meet design requirements, it is close until reaching design requirement that step (2) to (4) are repeated
Until degree.Under normal circumstances, cellular impregnation number is 2n times (n >=1), when the close non-impregnation honeycomb block density of target density
When, allow to reach design requirement density by 1 impregnation.
In step (1), the water soluble phenol resin is mid-temperature-cure resin, solidification temperature≤160 DEG C, water-soluble >=
600%, free phenol content≤5%.
In step (1), impregnating resin range of viscosities is 10cP~40cP.
In step (2), promoting velocity interval is 40mm/min~160mm/min.
In step (5), when each impregnation, the difference between cellular density lifting capacity is no more than ± 3kg/m3。
In step (5), when repeating impregnation, the direction of improvement tune of rear soaking honeycomb block and preceding soaking honeycomb block
Turn 180 °.
In step (3), the honeycomb cell horizontal positioned time is 45min~120min, flows impregnating resin adequately
It drops down on the corner to honeycomb hexagon.
In step (4), cellular temperature for removing water is 60 DEG C~90 DEG C after impregnation, and baking oven is warming up to tree after the completion of water removal
Initial reaction temperature precuring 5min~30min of rouge, then carry out second of dipping.Precuring can make resin surface be hardened, and keep away
Exempt from resin distribution situation to change in subsequent immersing glue process.
The solid content of the water soluble phenol resin original gelatin is 50%~75%.
Embodiment 1
Cell side length is 2.75mm, density 32kg/m3Raising water-soluble resin honeycomb core material compressive strength impregnation
Technique.Specific step is as follows:
(1) water soluble phenol resin and aqueous solvent are added in glue groove according to the ratio of 1:1, then pass through supplement appropriate
Resin and aqueous solvent, by the control of impregnating resin gelatin viscosity within the scope of 15 ± 3cP, wherein the water soluble phenol resin
Quality accounts for the 20%~30% of impregnating resin gross mass.
(2) selecting cell side length is the non-impregnation honeycomb block of 2.75mm, and non-impregnation honeycomb block density range is 22 ± 2kg/
m3, honeycomb block is put into steeping vat, after impregnating 30min~60min, with the promotion speed of 45mm/min~80mm/min by bee
Nest is proposed from glue, after each impregnation, by after impregnation honeycomb overturn 90 °, make honeycomb cell be horizontally arranged 30min~
120min avoids impregnating resin from controlling distribution of the resin in honeycomb cell while going out from the relaying afterflow of honeycomb cell, horizontal
The distribution situation to resin in honeycomb cell is needed to observe in placement process, it is ensured that resin integrated distribution is in honeycomb hexagon
On cellular angle, such as schematic diagram 2.
(3) honeycomb is after completing impregnating resin distributed controll, is carried out in an oven except water process, and temperature for removing water is 75 DEG C ±
10 DEG C, soaking time is 45min ± 10min, and except the spread for measuring single impregnation after water process, the control of single spread exists
5kg/m3~10kg/m3In range.2 impregnations are carried out to honeycomb block in present case honeycomb exists after first time impregnation, water removal
Precuring 15min ± 5min at 105 DEG C ± 10 DEG C.
(4) solidification is carried out according to the curing process of resin and piece cuts processing to except the honeycomb after the completion of water process, obtain close
Degree is 32kg/m3High compression-strength water-soluble resin honeycomb core material, the stable type compressive strength for testing the honeycomb core material is
1.3MPa, about 1.3 times of honeycomb core material stable type compressive strength prepared by same specification traditional handicraft, 60s vertical combustion performance
The results show that object, incipient scorch length are less than 150mm, meet HB 5469 " in civil aircraft cabin without dripping off during honeycomb test
Nonmetallic materials combustibility requirement " in index request.
Embodiment 2
Cell side length is 2.75mm, density 48kg/m3Raising water-soluble resin honeycomb core material compressive strength impregnation
Technique.Specific step is as follows:
(1) water soluble phenol resin and aqueous solvent are added in steeping vat according to the ratio of 1:1, then pass through benefit appropriate
Resin and aqueous solvent are filled, by the control of impregnating resin gelatin viscosity within the scope of 20 ± 3cP, wherein the water soluble phenol resin
Quality account for the 25%~40% of impregnating resin gross mass.
(2) selecting cell side length is the non-impregnation honeycomb block of 2.75mm, and non-impregnation honeycomb block density range is 22 ± 2kg/
m3, honeycomb block is put into steeping vat, it, will with the promotion speed of 60mm/min~120mm/min after impregnating 30min~60min
Honeycomb is proposed from glue, after each impregnation, by after impregnation honeycomb overturn 90 °, make honeycomb cell be horizontally arranged 30min~
120min avoids impregnating resin from controlling distribution of the resin in honeycomb cell while going out from the relaying afterflow of honeycomb cell, horizontal
The distribution situation to resin in honeycomb cell is needed to observe in placement process, it is ensured that resin integrated distribution is in honeycomb hexagon
On cellular angle, such as schematic diagram 2.
(3) honeycomb is after completing impregnating resin distributed controll, is carried out in an oven except water process, and temperature for removing water is 75 DEG C ±
10 DEG C, soaking time is 45min ± 10min, and except the spread for measuring single impregnation after water process, single spread should be controlled
7kg/m3~10kg/m3In range.4 impregnations are carried out to honeycomb block in present case, 3 times after impregnation, water removal, by honeycomb 105
Precuring 15min ± 5min at DEG C ± 10 DEG C.
(4) solidification is carried out according to the curing process of resin and piece cuts processing to except the honeycomb after the completion of water process, obtain close
Degree is 48kg/m3High compression-strength water-soluble resin honeycomb core material, the stable type compressive strength for testing the honeycomb core material is
3.0MPa, about 1.5 times of honeycomb core material stable type compressive strength prepared by same specification traditional handicraft, 60s vertical combustion performance
The results show that object, incipient scorch length are less than 150mm, meet HB 5469 " in civil aircraft cabin without dripping off during honeycomb test
Nonmetallic materials combustibility requirement " in index request.
Claims (9)
1. a kind of gum dipping process method for improving water-soluble resin honeycomb core material compressive strength, which is characterized in that successively soaked
The preparation of stain resin, impregnation, impregnating resin distributed controll, 4 step processing steps of water removal:
(1) impregnating resin configures: water soluble phenol resin being added in glue groove, is then added according to the ratio of 1:1 into glue groove
Water soluble phenol resin and aqueous solvent are measured impregnating resin viscosity by aqueous solvent after mixing, and impregnating resin range of viscosities is
5cP~60cP, temperature range are 23 ± 5 DEG C；
(2) impregnation: non-impregnation honeycomb block is put into impregnating resin, with the promotion speed of 10mm/min~200mm/min by bee
Nest block is lifted out impregnating resin liquid level；
(3) impregnating resin distributed controll: after honeycomb block is lifted out impregnating resin liquid level, 90 ° or 270 ° are overturn, by honeycomb hole
Lattice are horizontally arranged 30min~300min,
(4) it removes water: honeycomb core material after impregnation being carried out except water process at high temperature, temperature for removing water is 40 DEG C~100 DEG C, when water removal
Between be 15min~60min；
(5) when measurement honeycomb block density meet design requirements, repeating step (2) to (4) until reaching design requirement density is
Only.
2. a kind of gum dipping process method for improving water-soluble resin honeycomb core material compressive strength according to claim 1,
It is characterized in that, in step (1), the water soluble phenol resin is mid-temperature-cure resin, and solidification temperature≤160 DEG C are water-soluble
>=600%, free phenol content≤5%.
3. a kind of gum dipping process method for improving water-soluble resin honeycomb core material compressive strength according to claim 1,
It is characterized in that, in step (1), impregnating resin range of viscosities is 10cP~40cP.
4. a kind of gum dipping process method for improving water-soluble resin honeycomb core material compressive strength according to claim 1,
It is characterized in that, in step (2), promoting velocity interval is 40mm/min~160mm/min.
5. a kind of gum dipping process method for improving water-soluble resin honeycomb core material compressive strength according to claim 1,
It is characterized in that, in step (5), when each impregnation, the difference between cellular density lifting capacity is no more than ± 3kg/m3。
6. a kind of gum dipping process method for improving water-soluble resin honeycomb core material compressive strength according to claim 1,
It is characterized in that, in step (5), when repeating impregnation, the direction of improvement of rear soaking honeycomb block and preceding soaking honeycomb block
Turn 180 °.
7. a kind of gum dipping process method for improving water-soluble resin honeycomb core material compressive strength according to claim 1,
It is characterized in that, in step (3), the honeycomb cell horizontal positioned time is 45min~120min.
8. a kind of gum dipping process method for improving water-soluble resin honeycomb core material compressive strength according to claim 1,
It is characterized in that, in step (4), cellular temperature for removing water is 60 DEG C~90 DEG C after impregnation, is warming up to baking oven after the completion of water removal
Initial reaction temperature precuring 5min~30min of resin, then carry out second of dipping.
9. a kind of gum dipping process method for improving water-soluble resin honeycomb core material compressive strength according to claim 1,
It is characterized in that, the solid content of the water soluble phenol resin original gelatin is 50%~75%.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810809189.7A CN109049790B (en) | 2018-07-20 | 2018-07-20 | Impregnation process method for improving compression strength of water-soluble resin honeycomb core material |
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| CN201810809189.7A CN109049790B (en) | 2018-07-20 | 2018-07-20 | Impregnation process method for improving compression strength of water-soluble resin honeycomb core material |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111455723A (en) * | 2020-04-08 | 2020-07-28 | 长春珑鑫新材料有限公司 | Method for accurately controlling product density in production process of aramid paper honeycomb |
| CN113290944A (en) * | 2021-05-31 | 2021-08-24 | 芜湖创联新材料科技有限公司 | Method for manufacturing aramid paper honeycomb with uniform density |
| CN114193903A (en) * | 2021-12-07 | 2022-03-18 | 北京卫星制造厂有限公司 | Sizing method for honeycomb core material of spacecraft |
| CN117164787A (en) * | 2023-11-02 | 2023-12-05 | 北京玻钢院复合材料有限公司 | Modified phenolic resin for aramid paper honeycomb impregnation and preparation method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202606346U (en) * | 2012-05-31 | 2012-12-19 | 四川力通复合材料科技有限公司 | Rubber dip machine |
| CN107053768A (en) * | 2016-12-15 | 2017-08-18 | 中航复合材料有限责任公司 | A kind of preparation method of water soluble phenol resin comb core |
-
2018
- 2018-07-20 CN CN201810809189.7A patent/CN109049790B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202606346U (en) * | 2012-05-31 | 2012-12-19 | 四川力通复合材料科技有限公司 | Rubber dip machine |
| CN107053768A (en) * | 2016-12-15 | 2017-08-18 | 中航复合材料有限责任公司 | A kind of preparation method of water soluble phenol resin comb core |
Non-Patent Citations (2)
| Title |
|---|
| 刘杰等: "酚醛树脂分布对芳纶纸蜂窝力学性能的影响", 《宇航材料工艺》 * |
| 刘杰等: "高密度芳纶纸蜂窝的力学性能及应用前景分析", 《化学新型材料》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111455723A (en) * | 2020-04-08 | 2020-07-28 | 长春珑鑫新材料有限公司 | Method for accurately controlling product density in production process of aramid paper honeycomb |
| CN113290944A (en) * | 2021-05-31 | 2021-08-24 | 芜湖创联新材料科技有限公司 | Method for manufacturing aramid paper honeycomb with uniform density |
| CN114193903A (en) * | 2021-12-07 | 2022-03-18 | 北京卫星制造厂有限公司 | Sizing method for honeycomb core material of spacecraft |
| CN117164787A (en) * | 2023-11-02 | 2023-12-05 | 北京玻钢院复合材料有限公司 | Modified phenolic resin for aramid paper honeycomb impregnation and preparation method thereof |
| CN117164787B (en) * | 2023-11-02 | 2024-03-08 | 北京玻钢院复合材料有限公司 | Modified phenolic resin for aramid paper honeycomb impregnation and preparation method thereof |
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