CN110328916A - A kind of the sandwich thermal insulation material and preparation method of novel flame-retardant and electromagnetic shielding - Google Patents

Abstract

The invention discloses a novel flame-retardant and electromagnetic shielding sandwich thermal insulation material and a preparation method thereof. The invention provides a novel flame-retardant and electromagnetic shielding sandwich thermal insulation material and a preparation method thereof. agent, carbon fiber cloth and polysulfone fiber cloth, under the appropriate reaction temperature and time, a new type of electromagnetic shielding and flame-retardant composite non-woven fabric is prepared, and then the composite non-woven fabric is combined with the hard Polyurethane foam is compounded together. By designing the structure of polyurethane insulation materials, a new type of sandwich insulation material with excellent flame retardancy and electromagnetic shielding performance is prepared, which simplifies the processing technology and reduces costs. It has important economic and social benefits. .

Description

A novel flame-retardant and electromagnetic shielding sandwich insulation material and its preparation method

technical field

The invention relates to the technical field of preparation of composite materials, in particular to a novel flame-retardant and electromagnetic shielding sandwich insulation material and a preparation method thereof.

Background technique

Flame retardancy refers to the property of a substance or a material that has been treated to significantly delay the spread of flame. With the improvement of safety awareness, the requirements for flame retardancy of building materials, vehicles, home appliances and other materials are gradually increasing. There are many methods for evaluating flame retardancy, such as oxygen index measurement method, horizontal or vertical combustion test method, etc. In the past 10 years, a total of 31,000 high-rise building fires occurred nationwide, resulting in 474 deaths and direct property losses of 1.56 billion yuan. Since the building's thermal insulation exterior walls and furniture are highly flammable materials, they will burn completely once ignited within 5-10 minutes. At present, flammable materials are usually endowed with certain flame retardant properties by adding flame retardants and modified raw materials. Commonly used flame retardants include halogenated flame retardants and inorganic flame retardants. Halogenated flame retardants are currently the most produced flame retardants in the world, mainly represented by chlorine-based and brominated flame retardants. Because of their high flame-retardant efficiency and low price, they have been widely used in various fields for a long time. Although halogen-based flame retardants have good flame-retardant effects and a large market demand, they generate a large amount of smoke, corrosive and toxic gases that are harmful to humans and the environment when burned. Inorganic additive flame retardants have the advantages of low price, low toxicity, long-lasting flame retardant effect, less volatile precipitation and less smoke production, but problems such as excessive addition and large particle size will affect the mechanical properties of materials and polymer molding processes . Moreover, its disadvantages are also prominent. The flame retardant performance is poor, and a large filling amount is required to meet the flame retardant requirements, which has a great impact on the mechanical and mechanical properties of the substrate. Phosphorus-based flame retardants can work both in the gas phase and in the condensed phase, and will not produce toxic gases during combustion. Therefore, phosphorus-based flame retardants have gradually attracted people's attention.

With the rapid development of science and technology, the proliferation of various electronic devices in industrial and domestic environments has caused a lot of electromagnetic interference. Electromagnetic radiation has seriously affected people's lives, and has become another serious pollution in modern life that can be compared with water pollution and air pollution-electromagnetic pollution. At the same time, the problem of electromagnetic shielding has affected almost all electrical and electronic systems, from daily life to military activities to space exploration. Take a laptop computer as an example. Its power system can generate broadband electromagnetic radiation energy. This radiated energy can be transmitted and picked up by TV antennas, wireless remote controls, and any other equipment to cause abnormal performance. In addition, living organisms are often exposed to electromagnetic energy for a long time, which will increase the risk of various diseases, such as self-conscious neurological symptoms, cardiovascular dysfunction, reduced reproductive function, and cancer of various systems. Similarly, due to the presence of electromagnetic radiation, the use of mobile phones is not allowed during flights or in intensive care rooms of hospitals. Therefore, it is urgent to solve the problems of electromagnetic radiation and electromagnetic interference.

Aramid sulfone fiber, referred to as PSA fiber, is composed of polysulfoneamide. It is a new type of high-tech fiber product independently developed by my country. It has excellent heat resistance, flame retardancy and filtration performance, excellent physical and mechanical properties and chemical stability. The long-term use temperature of polysulfone fiber is 250°C, the strength retention rate after 100h heating is greater than 80%, and the limiting oxygen index (LOI) is 33%. Aramid sulfone fiber has been widely used in protective products, building materials, aerospace, national defense and military industry, etc. It is mixed with other fibers to make up for the defects of other fibers.

Carbon fiber has good electromagnetic shielding performance and is also a high-performance reinforcing fiber. At the same time, carbon fiber has excellent electrical and thermal conductivity, good flame retardancy, extremely low thermal expansion coefficient, low radiation absorption, non-magnetic and non-magnetized, excellent vibration damping, fatigue resistance and creep resistance. The main reason why carbon fiber has electromagnetic shielding ability is that it has good electrical conductivity. The common volume resistivity of carbon fiber is between (0.8～1.8)×10-3Ω·cm, and the electrical conductivity will increase with the increase of heat treatment temperature. Therefore, after high-temperature graphitization treatment, carbon fiber can become an excellent reflective material for electromagnetic waves. At present, domestic research on carbon fiber is still mainly focused on the mechanical properties of its composite materials, and there are relatively few researches in the field of electromagnetic shielding.

Existing flame-retardant electromagnetic shielding non-woven fabrics are mainly processed into flame-retardant and electromagnetic shielding non-woven fabrics through processes such as spinning, weaving and sizing. However, its technological process is relatively complicated and the cost is high, which cannot meet the needs of production.

Contents of the invention

In order to solve the shortcomings and deficiencies of the existing technology, a new type of flame-retardant and electromagnetic shielding sandwich insulation material and its preparation method are provided. By using a certain amount of water-based polyurethane, carbon fiber cloth and sulfonamide cloth, at an appropriate reaction temperature and time Next, a new type of electromagnetic shielding and flame-retardant composite non-woven fabric is prepared, and then the composite non-woven fabric is combined with rigid polyurethane foam through a "two-step method", and the structure of the polyurethane insulation material is designed to prepare A new sandwich insulation material with excellent flame retardancy and electromagnetic shielding performance has been produced, which shortens the processing process, reduces production costs, and has important economic and social benefits.

In order to realize the object of the present invention, a novel flame-retardant and electromagnetic shielding sandwich insulation material and its preparation method include composite non-woven fabric and rigid polyurethane foam, and the composite non-woven fabric is provided with upper, middle and lower three layer, the rigid polyurethane foam is filled between two composite non-woven fabrics, and the composite non-woven fabric is composed of carbon fiber cloth, adhesive, and polysulfonamide cloth.

As a further improvement of the above solution, the adhesive is set to be water-based polyurethane.

As a further improvement of the above scheme, the following steps are included:

Step 1: Apply the adhesive evenly on the carbon fiber cloth and the sulfonamide cloth, compound the two together, dry them in a constant temperature and humidity environment to prepare the composite nonwoven fabric;

Step 2: Stir polyether polyol and phosphorus-based flame retardant evenly, then add isocyanate for secondary stirring to prepare the rigid polyurethane foam, and then quickly inject it into the upper and lower layers covered with the composite nonwoven The cloth is integrally formed in the mold, and the mold is demoulded after curing to obtain the pre-finished product;

Step 3: Stir polyether polyol and phosphorus-based flame retardant evenly, then add isocyanate for secondary stirring to prepare the rigid polyurethane foam, and inject it into the upper layer covered with composite non-woven fabric, and the lower layer covered with Integral molding in the mold of the pre-finished product, demoulding after curing, to obtain a sandwich insulation material with flame retardant and electromagnetic shielding properties.

As a further improvement of the above solution, the mass ratio of polyether polyol, phosphorus-based flame retardant, and isocyanate in the second step is 5:1:5.

As a further improvement of the above scheme, the stirring speed of the polyether polyol and the phosphorus-based flame retardant in the step 2 and step 3 is 1200rpm/min, and the stirring time is 15min; the speed of adding the isocyanate for secondary stirring is 1200rpm /min, the stirring time is 12-16s.

As a further improvement of the above scheme, the preparation of the composite non-woven fabric in the first step is as follows: the adhesive is evenly coated on the carbon fiber cloth and the sulfonamide cloth through a high-pressure liquid gun, and the two are composited together , dried in an environment of 80°C to 100°C, and then dried in a constant temperature and humidity environment with a temperature of 25°C and a humidity of 53%.

As a further improvement of the above scheme, in the first step, the drying temperature is 90° C., and the drying time is 10-15 minutes.

As a further improvement of the above solution, the phosphorus-based flame retardant in the second step is set to be a phosphoric ester flame retardant.

As a further improvement of the above scheme, in the second step, the curing time is set to 1 h.

As a further improvement of the above scheme, in the steps two and three, the length, width, and height of the mold are set to 350mm, 330mm, and 10mm in sequence; the length and width of the composite nonwoven fabric produced in step one are 350mm, 330mm; The length, width and height of the pre-finished product produced in the step 2 are 350mm, 330mm and 10mm in sequence; the length, width and height of the sandwich insulation material produced in the step 3 are 350mm, 330mm and 20mm in sequence. The binder in step 1 is set to 25g, and the amount of polyether polyol, phosphorus flame retardant and isocyanate in step 2 is 90g, 18g and 90g respectively.

The beneficial effects of the present invention are:

Compared with the prior art, the present invention provides a new flame-retardant and electromagnetic shielding sandwich insulation material and its preparation method. In the present invention, by using a certain amount of adhesive, carbon fiber cloth and sulfonamide cloth, in an appropriate Under the reaction temperature and time, a new type of electromagnetic shielding and flame-retardant composite non-woven fabric is prepared, and then the composite non-woven fabric is combined with rigid polyurethane foam through a "two-step method". Design and prepare a new sandwich insulation material with excellent flame retardancy and electromagnetic shielding performance, which simplifies the processing technology and reduces the cost, and has important economic and social benefits.

Description of drawings

Below in conjunction with accompanying drawing, specific embodiment of the present invention is described in further detail, wherein:

Fig. 1 is the structural representation of sandwich insulation material of the present invention;

Fig. 2 is a characterization diagram of flame retardancy and electromagnetic shielding of the sandwich insulation material of the present invention.

Detailed ways

As shown in Figure 1, a novel flame-retardant and electromagnetic shielding sandwich insulation material provided by the present invention includes composite non-woven fabric and rigid polyurethane foam, and the composite non-woven fabric is provided with upper, middle and lower layers. The high-quality polyurethane foam is filled between two composite non-woven fabrics, and the composite non-woven fabric is composed of carbon fiber cloth, adhesive, and polysulfone fiber cloth. Specifically, the adhesive is set to be water-based polyurethane.

The preparation method includes the following steps: Step 1: Apply the adhesive evenly on the carbon fiber cloth and the sulfonamide cloth, compound the two together, dry them in a constant temperature and humidity environment to prepare a composite Non-woven fabric; Step 2: After stirring the polyether polyol and phosphorus-based flame retardant evenly, then add isocyanate for secondary stirring to prepare rigid polyurethane foam, (wherein, the phosphorus-based flame retardant is set as phosphate ester flame-retardant agent) and then quickly inject it into the mold where the upper layer and the lower layer are covered with composite non-woven fabrics for integral molding, and demould after curing to obtain a pre-finished product; step 3: prepare the rigid polyurethane foam in step 2, and inject it The upper layer is covered with a composite non-woven fabric, and the lower layer is covered with a pre-finished product, which is integrally formed in a mold. After curing for 1 hour, it is released from the mold to obtain a sandwich insulation material with flame retardant and electromagnetic shielding properties.

The preparation of the composite non-woven fabric in step 1 is as follows: the adhesive, that is, water-based polyurethane, is evenly coated on the carbon fiber cloth and the polysulfone fiber cloth through a high-pressure liquid gun, and the two are combined together, and the temperature is 80 ° C to 100 ° C. °C environment, and then dried in a constant temperature and humidity environment of 25 °C. After testing at 70°C, 90°C, and 110°C for 10 minutes, it was found that the adhesion at 70°C was poor; at 110°C, the water-based polyurethane was aging; so first select 90°C, and then at 90°C, different drying times 5min, 10min, 15min to react, 10min to achieve good adhesion, so choose 10min.

In step 2 and step 3, the mass ratio of polyether polyol, phosphorus-based flame retardant, and isocyanate is 5:1:5, and the stirring speed of polyether polyol and phosphorus-based flame retardant in step 2 and step 3 is 1200rpm/min, the stirring time is 15min; the speed of adding isocyanate for secondary stirring is 1200rpm/min, and the stirring time is 12-16s. In practical applications, the length, width, and height of the mold can be set to 350mm, 330mm, and 10mm in turn; correspondingly, the length and width of the composite non-woven fabric produced in step 1 are 350mm and 330mm; The length, width, and height of the pre-finished product are 350mm, 330mm, and 10mm in sequence; the length, width, and height of the sandwich insulation material prepared in step 3 are 350mm, 330mm, and 20mm in sequence. Correspondingly, the adhesive in step 1, That is, the water-based polyurethane is set to 25g. After testing the water-based polyurethane (15g, 20g, 25g, 30g), it is found that 25g of water-based polyurethane can just cover the carbon fiber cloth and sulfonamide cloth of 350mm×330mm. At this time, the thickness of the water-based polyurethane is about It is 20um. Correspondingly, the preparation of rigid polyurethane foam in step 2 is as follows: take 90g of polyether polyol and 18g of phosphorus-based flame retardant, use a DC servo electric mixer at 1200rpm/min to stir for 15min, and then add 90g of isocyanate at 1200rpm/min Stir for 12s-16s. Among them, the model of the DC servo electric mixer is set as S569T2/A3. After testing, it is found that the limiting oxygen index of the sandwich insulation material made by the present invention is 27%, and the electromagnetic shielding value can reach 40dB, as shown in FIG. 2 .

The above embodiments are not limited to the technical solutions of the embodiments themselves, and the embodiments can be combined with each other to form new embodiments. The above embodiments are only used to illustrate the technical solution of the present invention and not to limit it. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall fall within the scope of the technical solution of the present invention.

Claims (10)

1. the sandwich thermal insulation material of a kind of novel flame-retardant and electromagnetic shielding, it is characterised in that: include compound nonwoven cloth and Hard polyurethane foams, the compound nonwoven cloth are provided with upper, middle and lower-ranking, and the hard polyurethane foams are filled in two-by-two Between compound nonwoven cloth, the compound nonwoven cloth is combined by carbon cloth, adhesive, PSA fiber cloth.

2. the preparation method of the sandwich thermal insulation material of a kind of novel flame-retardant according to claim 1 and electromagnetic shielding, Be characterized in that: described adhesive is set as aqueous polyurethane.

3. the preparation method of the sandwich thermal insulation material of a kind of novel flame-retardant according to claim 1 and electromagnetic shielding, It is characterized in that:

Include following steps: step 1: adhesive is evenly coated on carbon cloth and PSA fiber cloth, and the two is compound Together, it after drying, dries in constant-temperature constant-humidity environment to prepare the compound nonwoven cloth；

Step 2: it after mixing evenly by the pure and mild phosphorus flame retardant of polyether polyols, adds isocyanates and carries out secondary agitation, produce Then the hard polyurethane foams are quickly injected into the upper and lower and are all covered with one in the mold of the compound nonwoven cloth Molding, curing and demolding obtain preform；

Step 3: it after mixing evenly by the pure and mild phosphorus flame retardant of polyether polyols, adds isocyanates and carries out secondary agitation, produce The hard polyurethane foams, and be injected into upper layer and be covered with compound nonwoven cloth, lower layer is covered in the mold of the preform It is integrally formed, curing and demolding, obtains that there is fire-retardant and electromagnetic shielding performance sandwich thermal insulation material.

4. the preparation method of the sandwich thermal insulation material of a kind of novel flame-retardant according to claim 3 and electromagnetic shielding, Be characterized in that: polyether polyol in the step 2, phosphorus flame retardant, isocyanates quality proportioning be 5:1:5.

5. the preparation method of the sandwich thermal insulation material of a kind of novel flame-retardant according to claim 3 and electromagnetic shielding, It is characterized in that: by the revolving speed of polyether polyols pure and mild phosphorus flame retardant stirring being 1200rpm/min in the step 2 and step 3, Mixing time is 15min；The isocyanates that is added carries out the revolving speed of secondary agitation as 1200rpm/min, mixing time 12- 16s。

6. the preparation method of the sandwich thermal insulation material of a kind of novel flame-retardant according to claim 3 and electromagnetic shielding, It is characterized in that: the preparation of compound nonwoven cloth in the step 1 specifically: described adhesive is uniformly coated by high pressure liquid rifle On carbon cloth and PSA fiber cloth, the two is combined with each other, is dried in 80 DEG C~100 DEG C environment, is then in temperature 25 DEG C, humidity is made for drying in 53% constant-temperature constant-humidity environment.

7. the preparation method of the sandwich thermal insulation material of a kind of novel flame-retardant according to claim 3 and electromagnetic shielding, Be characterized in that: drying temperature is 90 DEG C in the step 1, and drying time is 10~15 minutes.

8. the preparation method of the sandwich thermal insulation material of a kind of novel flame-retardant according to claim 3 and electromagnetic shielding, Be characterized in that: phosphorus flame retardant is set as phosphate flame retardant in the step 2.

9. the preparation method of the sandwich thermal insulation material of a kind of novel flame-retardant according to claim 3 and electromagnetic shielding, Be characterized in that: in the step 2, curing time is set as 1h.

10. the preparation method of the sandwich thermal insulation material of a kind of novel flame-retardant according to claim 3 and electromagnetic shielding, Be characterized in that: in the step 2 and step 3, the length of mold is set gradually as 350mm, 330mm, 10mm；Step 1 In the compound nonwoven cloth length and width produced be 350mm, 330mm；The preform length produced in the step 2 is followed successively by 350mm,330mm,10mm；The sandwich thermal insulation material length produced in the step 3 be followed successively by 350mm, 330mm, 20mm, adhesive described in the step 1 are set as 25g, polyether polyol in the step 2, phosphorus flame retardant and different The dosage of cyanate is respectively 90g, 18g and 90g.