CN211005206U

CN211005206U - Foam with thermal self-expansion function

Info

Publication number: CN211005206U
Application number: CN201920622496.4U
Authority: CN
Inventors: 蔡锦云; 李卫平; 谢容泉; 李步龙; 官江全
Original assignee: XIAMEN HOWER MATERIAL CO Ltd
Current assignee: XIAMEN HOWER MATERIAL CO Ltd
Priority date: 2019-04-30
Filing date: 2019-04-30
Publication date: 2020-07-14
Anticipated expiration: 2029-04-30

Abstract

The utility model discloses a foam body with thermal self-expansion function. The inner layer of the foam body with the thermal self-expansion function is hard foam, and the outer layer of the foam body with the thermal self-expansion function is thermal self-expansion resin. The thermal self-expansion resin and the hard foam are integrally formed, so that fewer bubbles are formed on the interface, the binding force is stronger, and the strength of the product is uniformly improved. Meanwhile, the integrally formed foam structure has the effect of being suitable for forming special-shaped products. The foam with the thermal self-expansion function is used for preparing a sandwich composite material structural member, has excellent performances of high strength, light weight, good interlayer bonding, difficult delaminating and splitting, impact resistance and the like, and can be applied to the field of sandwich structure composite materials with complex structures.

Description

Foam with thermal self-expansion function

Technical Field

The utility model relates to a fibre combined material shaping field especially relates to a foam of thermal self-expansion function.

Background

The rigid foam material has the advantages of small density, strong energy absorption and buffering capacity, good sound absorption performance and the like, and is often used for the design of a sandwich structure, so that the sandwich structure material has excellent performances different from the traditional structure material, such as light weight, high rigidity, high strength and the like. Has wide application prospect in the aspects of aerospace, automobile manufacturing, sports and leisure and the like. The most typical sandwich structure composite material in the prior art usually consists of a panel (carbon fiber or glass fiber reinforced material), a core material (rigid foam) and a cementing layer, and the common preparation method is to coat the cementing layer on the rigid foam, then coat a carbon cloth/glass cloth prepreg and further form a product.

The problems existing in the prior art are as follows:

1. in order to match the carbon fiber or glass fiber reinforced material surface layer and the rigid foam core material of the formed product, the bonding is firm, and the delamination is avoided, a cementing layer is required to be used, and the working procedure and the cost are increased.

2. Because the temperature resistance of some rigid foams is poor, the rigid foams cannot bear the molding temperature of 140-180 ℃ of the common carbon fiber or glass fiber reinforced material, namely, the high-temperature shrinkage, the appearance of the product is poor in the molding process, and the rejection rate is increased.

3. The cementing layer and the hard foam have no outward expansion pressure, so that the compression molding product has apparent defects of rubber shortage and the like, and the post-repair process is added.

4. Patent CN 107901449A "preparation method of composite material structure of light high-strength high-energy glue-rigid foam" discloses a composite material structure of light high-strength high-energy glue-rigid foam, the structure is: the inner layer is hard foam, the middle is wrapped with high-energy glue, and the outer layer is fiber prepreg cloth. Although the problems in the two aspects can be solved, the problems that the high-energy adhesive is not enough in viscosity and poor in initial viscosity with the rigid foam, and particularly when a complex part is manufactured, the interlayer attaching operation of the high-energy adhesive and the rigid foam is difficult to ensure that no bubbles exist completely, so that the operation is not easy are solved. Simultaneously the utility model discloses it is more convenient in the use, reduced tailor and wrapped up the process that the high energy was glued outside the rigid foam core.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a rigid foam combined material's intermediate structure.

In order to achieve the above object, the present invention provides a foam body with thermal self-expansion function, wherein the inner layer is rigid foam, the outer layer is thermal self-expansion resin, and the rigid foam and the thermal self-expansion resin are integrally formed.

Further, the density of the rigid foam is 30-300kg/m³。

Further, the rigid foam is PU, PVC, PET, PMI, PEI, PP, EVA, EPS.

Further, the thickness of the thermal self-expansion resin layer is 0.05-0.5 mm.

Further, the thermal self-expansion resin comprises 30-70 parts by weight of thermosetting resin, 0-20 parts by weight of toughening agent, 1-20 parts by weight of foaming agent and 0-20 parts by weight of diluent; 0-30 parts by weight of flame retardant is sequentially added into a stirring barrel and uniformly stirred to obtain the flame retardant; the free expansion multiplying power of the thermal self-expansion resin layer is 1-20 times, and the expansion pressure is 0.1-20 MPa.

Further, the thermosetting resin is epoxy resin or phenolic resin;

optionally, the toughening agent is a rubber toughening agent or a thermoplastic resin; preferably, the rubber toughening agent is liquid polysulfide rubber or liquid nitrile rubber; the thermoplastic resin is polyether sulfone, polysulfone, polyimide or polyphenyl ether;

optionally, the foaming agent is a chemical foaming agent or a physical foaming agent, preferably, the chemical foaming agent is azodiisobutyronitrile or azodicarbonamide, and the physical foaming agent is expandable microspheres;

optionally, the diluent is a reactive diluent or an organic solvent; preferably, the reactive diluent is 1, 4-butanediol diglycidyl ether or C12-14 fatty glycidyl ether, and the organic solvent is esters or ketones;

optionally, the flame retardant is an additive flame retardant or an inorganic flame retardant or a reactive flame retardant; preferably, the additive flame retardant is bromine, phosphorus nitrogen or nitrogen, and the inorganic flame retardant is antimony trioxide, magnesium hydroxide, aluminum hydroxide or silicon; the reactive flame retardant is 2, 3-dibromopropanol, dibromophenol or tetrabromophthalic anhydride.

Further, the preparation method comprises the following steps:

cutting: cutting the rigid foam according to the size of the product;

spraying or pouring: the spraying is to spray a layer of thermal self-expansion resin on the outer layer of the rigid foam; the pouring is to fill the cut rigid foam into a mold, and then pour the thermal self-expansion resin into the mold; opening the mold and taking out.

Further, the spraying is manual spraying or full-automatic spraying for uniformly spraying the thermal self-expansion resin on the outer layer of the hard foam, and the spraying mode is traditional air spraying or thermal spraying; preferably, the spraying is carried out for 1 to 3 times by adopting a cross spraying method.

Optionally, the pouring mode is normal pressure or the mould is vacuumized and then is introduced into the thermal self-expansion resin; the perfusion rate is 1-2 Kg/min.

Further, in the spraying or pouring step, the thickness of the thermal self-expansion resin layer is 0.05-0.5 mm.

The utility model also provides a preparation method of the foam body with the thermal self-expansion function, which comprises the following steps,

cutting: cutting the rigid foam according to the size of the product;

Optionally, the spraying is manual spraying or full-automatic spraying for uniformly spraying the thermal self-expansion resin on the outer layer of the rigid foam, and the spraying mode is traditional air spraying or thermal spraying; preferably, the spraying is carried out for 1 to 3 times by adopting a cross spraying method.

Optionally, the pouring mode is normal pressure or the mould is vacuumized and then is introduced into the thermal self-expansion resin; the perfusion rate is 1-2 Kg/min. The pouring is to fix the rigid foam in the mould, and then pour the thermal self-expansion resin into the mould to fill the cavity between the rigid foam and the mould.

The thermal self-expansion resin of the utility model has proper fluidity at normal temperature or 50-100 ℃, has a viscosity range of 15-40s (coating 4 cups for testing), and meets the process requirements of spraying and filling.

The thermal self-expansion resin layer of the utility model can effectively solve the problems of scrapping caused by shrinkage of hard foam under high temperature condition and bad appearance of products in the compression molding process by thermal expansion;

the utility model discloses a heat plays the effect that rigid foam and surface course bond simultaneously from the inflation resin layer to just viscidity is strong, effectively eliminates bubble between the interface layer, the operation of being convenient for.

The utility model discloses a heat is from expanded resin and stereoplasm foam integrated into one piece, the bubble at interface still less, and the cohesion is stronger, is favorable to even promotion goods intensity. Meanwhile, the integrally formed foam structure has the effect of being suitable for forming different-shaped products.

The utility model discloses a heat is from inflation resin layer can add the fire retardant composition, and the goods that prepare after adding and obtain have better flame retardant efficiency.

Foam body of hot self-expanding function is used for preparing double-layered core combined material structure, has excellent properties such as intensity height, quality light, interlayer bonding, difficult delaminating split, shock-resistant, can be applied to the sandwich structure composite material field of complex construction.

Drawings

Figure 1 is a schematic cross-sectional view of a foam structure with thermal self-expansion functionality according to the present invention.

FIG. 2 is a schematic cross-sectional view of the structure of an article resulting from the application of the foam with thermal self-expansion functionality.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention. The examples do not specify particular techniques or conditions, and are performed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

The composition of the thermal self-expanding resin of the following examples is 30-70 parts by weight of thermosetting resin, 0-20 parts by weight of toughening agent, 1-20 parts by weight of foaming agent, 0-20 parts by weight of diluent; 0-30 parts by weight of flame retardant is sequentially added into a stirring barrel and uniformly stirred to obtain the flame retardant; the free expansion multiplying power of the thermal self-expansion resin layer is 1-20 times, and the expansion pressure is 0.1-20 MPa.

Optionally, the thermosetting resin is epoxy resin or phenolic resin;

The rigid foam can be PU, PVC, PET, PMI, PEI, PP, EVA and EPS.

The thickness of the thermal self-expansion resin is 0.05-0.5 mm.

Example 1: foam with thermal self-expansion function

The structure is shown in figure 1. Wherein 1 is a thermal self-expanding resin, 2 is a rigid foam, and 3 is a mold. The thickness of the thermal self-expanding resin is 0.3 mm.

The preparation method comprises the following steps:

cutting: cutting the rigid foam according to the size of the product;

spraying: spraying a layer of thermal self-expansion resin on the outer layer of the rigid foam. The thickness of the coating is 0.1mm by adopting a mode of crisscross spraying once.

The prepared foam with the thermal self-expansion function comprises the following steps:

the initial stickiness was touched with a finger pressing the surface of the hot self-expanding resin layer for 15s, and the resin layer stuck to the hand but not transferred to the finger;

the prepared foam is put into an oven at 150 ℃ to be heated for 30 minutes, and the foaming ratio (volume ratio before and after heating) is 1: 1.18.

the prepared foam is put into an isometric closed mould and heated at 150 ℃, and the generated expansion pressure is 0.11 Mpa.

Example 2: preparation of foams with thermal self-expansion function

The structure is shown in figure 1. Wherein 1 is a thermal self-expanding resin, 2 is a rigid foam, and 3 is a mold. The thickness of the thermal self-expanding resin is 0.1 mm.

The preparation method comprises the following steps:

cutting: cutting the rigid foam according to the size of the product;

spraying: spraying a layer of thermal self-expansion resin on the outer layer of the rigid foam. The coating thickness is 0.3mm by adopting a cross spraying mode for three times.

the initial stickiness was touched with a finger pressing the surface of the hot self-expanding resin layer for 5s, and the resin layer stuck to the hand but not transferred to the finger;

the prepared foam is put into an oven at 150 ℃ to be heated for 30 minutes, and the foaming ratio (volume ratio before and after heating) is 1: 1.46.

the prepared foam is put into an isometric closed mould and heated at 150 ℃, and the generated expansion pressure is 0.58 Mpa.

Example 3: preparation of foams with thermal self-expansion function

The structure is shown in figure 1. Wherein 1 is a thermal self-expanding resin, 2 is a rigid foam, and 3 is a mold. The thickness of the thermal self-expanding resin is 0.5 mm.

The preparation method comprises the following steps:

cutting: cutting the rigid foam according to the size of the product;

pouring: filling the cut rigid foam into a mold, and then pouring thermal self-expansion resin into the mold; opening the mold and taking out.

The amount of the thermal self-expandable resin required was calculated as 1.1 times the volume of the cavity between the rigid foam and the mold (which means that the amount of the thermal self-expandable resin used was 1.1 times or less the volume of the space between the rigid foam and the mold).

The perfusion rate was controlled at 1.5 kg/min.

initial stickiness by finger touch, pressing the surface of the thermal self-expansion resin layer for 8s by a finger, and sticking the resin layer to the hand without transferring to the finger;

the prepared foam is put into an oven at 150 ℃ to be heated for 30 minutes, and the foaming ratio (volume ratio before and after heating) is 1: 1.1.

the prepared foam is put into an isometric closed mould and heated at 150 ℃, and the generated expansion pressure is 0.1 Mpa.

Example 4: preparation of foams with thermal self-expansion function

The structure is shown in figure 1. Wherein 1 is a thermal self-expanding resin, 2 is a rigid foam, and 3 is a mold. The thickness of the thermal self-expanding resin is 0.05 mm.

The preparation method comprises the following steps:

cutting: cutting the rigid foam according to the size of the product;

Calculating the required amount of the thermal self-expansion resin according to 1.1 times of the volume of a cavity between the rigid foam and the mold;

the perfusion rate was controlled at 2 kg/min.

initial tack by finger touch, pressing the surface of the thermal self-expansion resin layer for 10s by a finger, and sticking the resin layer to the hand without transferring to the finger;

the prepared foam is put into an oven at 150 ℃ to be heated for 30 minutes, and the foaming ratio (volume ratio before and after heating) is 1: 1.35.

the prepared foam is put into an isometric closed mould and heated at 150 ℃, and the generated expansion pressure is 0.42 Mpa.

Example 5: use of thermally self-expandable foams

The structure of the resulting article is shown in FIG. 2, where 1 is a thermally self-expanding resin, 2 is a rigid foam, and 4 is a fiber prepreg.

The using method comprises the following steps:

1) and cutting the carbon cloth or glass cloth prepreg.

2) According to the structural design, the thermal self-expansion functional foam obtained in any one of the embodiments 1 to 4 is externally wrapped with a carbon cloth/glass cloth prepreg.

3) Placing into a mold for molding: the molding temperature is 100 ℃ and 200 ℃. The molding time is 10-120 min.

4) Cooling, demoulding and taking out the product. The structural schematic cross-sectional view of the article is shown in fig. 2.

Preparation of comparative example:

1) the rigid foam is cut according to the size of the article.

2) And coating a cementing layer on the hard foam outer layer.

3) And (3) coating the carbon cloth/glass cloth prepreg according to the structural design.

4) Placing into a mold for molding: the molding temperature is 100 ℃ and 200 ℃. The molding time is 10-120 min.

5) Cooling, demoulding and taking out the product.

Comparative experiments comparing the effects of example 5 and comparative example are shown in table 1.

Table 1 comparative experimental table for effects of example 5 and comparative example

Density of the product: calculated as product mass divided by product volume.

Bending strength: bending performance testing with reference to ISO 14125 fibre reinforced plastic composites.

Impact resistance: the balls of a certain mass were dropped from different heights repeatedly, and the number of times the prepreg cloth delaminated from the foam was recorded.

As can be seen from Table 1, the product of the present invention has lower density, better bending strength and better impact resistance compared with the comparative example.

The obtained product has the following excellent effects:

1) the density of the thermal self-expansion resin layer after thermal expansion is 50-1000kg/m³Reduced to 10kg/m³Has a density of 30-300kg/m higher than that of pure rigid foam³Lower, the resulting article is lighter in weight;

2) the thermal self-expansion resin has an expansion force, so that the defects of poor product appearance and the like caused by high-temperature shrinkage of pure rigid foam are overcome, and the product appearance has no defects of glue deficiency, pinholes and the like;

3) the interlayer combination of the fiber prepreg cloth is tighter, and the mechanical strength of the product (compared with pure rigid foam) is improved by more than 10 percent;

4) the comprehensive cost is reduced by more than 30 percent (compared with pure rigid foam);

5) the operation flow is shortened, the working procedures are saved, and the product yield is improved;

6) by adding the flame retardant component, the flame retardant grade of the thermal self-expansion resin layer can reach U L94-V0, and the application field of the thermal self-expansion resin layer is widened;

7) the bonding strength of the rigid foam and the fiber prepreg is improved, delamination is not easy to occur, the impact resistance of the product is improved by more than 10%, and the test conditions of high-temperature and low-temperature alternating experiments can be met.

Although embodiments of the present invention have been shown and described, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that changes, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art without departing from the principles and spirit of the present invention.

Claims

1. A foam body with a thermal self-expansion function, characterized in that an inner layer is rigid foam, an outer layer is thermal self-expansion resin, and the rigid foam and the thermal self-expansion resin are integrally molded.

2. The thermally self-expanding functional foam according to claim 1, wherein said rigid foam has a density of 30 to 300kg/m³。

3. Thermal self-expanding functional foam according to claim 1, characterised in that said rigid foam is PU, PVC, PET, PMI, PEI, PP, EVA, EPS.

4. The thermally self-expandable functional foam according to claim 1, wherein the thickness of the thermally self-expandable resin is 0.05 to 0.5 mm.