CN111321610B - High-flame-retardant leather and preparation method thereof - Google Patents

Abstract

The invention relates to the field of leather, in particular to high-flame-retardant leather. The key points of the technical scheme are as follows: the leather coating comprises a coating layer, a bonding layer and a leather layer which are sequentially arranged from outside to inside, wherein the coating layer is made of a silica gel material. The silica gel material is incombustible and can not be ventilated, when flame is not vigorous and only flames are available, the coating layer of the silica gel material can furthest isolate oxygen in the air from contacting with the leather, and when the flame is vigorous and the temperature is high, the silica gel material fills the pores of the leather layer after being heated and melted, so that the combustion of the leather is greatly delayed, and the flame retardance of the leather is greatly increased.

Description

High-flame-retardant leather and preparation method thereof

Technical Field

The invention relates to the field of leather, in particular to high-flame-retardant leather.

Background

The leather industry has been rapidly developed in recent decades, and people have increasingly growing demand for leather, so that the safety performance of leather is increasingly required. The leather as a natural high polymer contains C, H, O, N elements, and can release CO and CO when being burnt ₂ Nitrogen oxide and the like, especially in the scenes of air crash, fire and the like, the smoke generated by the combustion of the leather greatly threatens the life safety of people, so that the flame retardant property of the leather is enhanced, and precious time can be won for emergency escape, fire scene evacuation and fire rescue of people.

Most people in the prior art adopt some flame retardant materials to make leather obtain flame retardant, for example, PCT international application with publication No. CN104364439B discloses a synthetic leather with flame retardant properties, whose skin resin contains an organic phosphorus compound to make synthetic leather obtain better flame retardant properties. The Chinese patent with application publication number CN109705307A discloses fluorescent flame-retardant waterborne polyurethane, a film and a preparation method thereof, and the technical scheme is characterized in that the surface coating layer using the waterborne polyurethane as a film forming agent is provided, and the flame retardant effect is still obtained by an organic phosphorus flame retardant. The patent of Chinese invention with the publication number of CN106632958B provides flame retardant waterborne polyurethane based on a reactive graphene flame retardant, the polyurethane is used as a coating material of leather, and the flame retardancy of graphene is mainly utilized to enable the whole leather to obtain a good flame retardant effect.

From the prior art, the research directions of the prior art are about two, wherein one research and development direction is to research and develop a novel flame retardant to be added into the leather surface finishing agent, and the other research and development direction is to improve and apply some existing flame retardants to some film forming agents which are more environment-friendly and more meet the performance requirements. The reason for this phenomenon is mainly that people generally believe that the leather coating needs to use resin with good film-forming property as the leather finishing agent, and the technical prejudice hinders people's research on flame-retardant leather.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the high-flame-retardant leather, which adopts silica gel as a finishing agent and can ensure that the leather has better flame-retardant performance without using a flame retardant.

The technical purpose of the invention is realized by the following technical scheme: the high-flame-retardant leather comprises a coating layer, a bonding layer and a leather layer which are sequentially arranged from outside to inside, wherein the coating layer is made of a silica gel material.

By adopting the technical scheme, the silica gel material can not be combusted and can not be ventilated, when flame is not vigorous and only flames are generated, the coating layer made of the silica gel material can isolate oxygen in the air from contacting with leather to the maximum extent, when the flame is vigorous and the temperature is high, the silica gel material fills the pores of the leather layer after being heated and melted, the combustion of the leather is greatly delayed, and the flame retardance of the leather is greatly increased.

Preferably, the silica gel material of the coating layer is prepared from the following components in percentage by mass:

10-25% of hydrogen-containing silicone oil;

0.6-1% of platinum catalyst;

1-2% of pigment;

the balance of raw rubber.

By adopting the technical scheme, the hydrogen-containing silicone oil and the raw rubber are necessary materials for preparing the silica gel, the platinum catalyst is an initiator capable of initiating the silica gel to be crosslinked, and the pigment can endow the coating layer with various colors and glosses, so that the attractiveness of the high-flame-retardant leather is improved. The silica gel material prepared by the proportion has good coating performance and can be better used as a coating layer of leather.

Preferably, the raw rubber is prepared from the following components in percentage by mass:

25-30% of fumed silica;

6-8% of a silane coupling agent;

0.6-1% of platinum catalyst;

the balance of methyl vinyl silicone oil.

By adopting the technical scheme, the silane coupling agent is a reagent for crosslinking inorganic silicon and organic silicon, the platinum catalyst is a reagent for polymerizing methyl vinyl silicone oil together, the fumed silica is used as an inorganic aggregate and can improve the wear resistance of the silica gel material coating layer to a certain extent after being crosslinked with the methyl vinyl silicone oil, the methyl vinyl silicone oil contains a large amount of inert methyl groups and active vinyl groups, and the vinyl groups have certain adhesive property and can improve the peeling strength of the whole coating layer relative to a leather layer.

Preferably, the methyl vinyl silicone oil is prepared from the following substances in percentage by mass:

8-15% of dimethyl siloxane mixed ring body;

5-15% of vinyl double end enclosure;

1-2% of alkali glue;

3-5% of dimethyl silicone oil;

octamethylcyclotetrasiloxane balance;

in the vinyl double-end socket, the content of tetramethyl divinyl disiloxane is 50%, the viscosity of the dimethyl silicone oil is 800-1200cps, and the viscosity of the obtained methyl vinyl silicone oil is 5000-8000 cps.

By adopting the technical scheme, the vinyl double-end socket is used as a main source of vinyl in the methyl vinyl silicone oil, the other organic silicon is used as a methyl source of the methyl vinyl silicone oil, and the alkali glue is a catalyst for catalyzing the polymerization of various substances. The viscosity of the methyl vinyl silicone oil is very critical, and the practice proves that the viscosity of the methyl vinyl silicone oil is 5000-8000cps, and the finally obtained silica gel coating has high hardness and good wear resistance.

Preferably, the leather layer is made of superfine fiber PU synthetic leather.

By adopting the technical scheme, the superfine fiber PU synthetic leather is prepared by adding superfine fiber into PU polyurethane, so that the toughness, air permeability and wear resistance are further enhanced; the superfine fiber PU synthetic leather has extremely excellent wear resistance, and excellent cold resistance, air permeability and aging resistance.

Preferably, the thickness of the coating layer is 0.15-0.25mm, the thickness of the bonding layer is 0.05-0.15mm, and the thickness of the leather layer is 0.3-0.6 mm.

Through adopting above-mentioned technical scheme, the decoration layer hardness on leather layer is big, sets up thinner decoration layer and can not influence leather tensile property, and the thickness of tie coat then selects the thickness that just can firmly bond decoration layer and leather layer, and the leather layer should not be too thin, and thin then can lead to the leather too fragile, and the leather layer should not too thick equally, and the leather layer quality of too thick is great, and the cost is higher.

Preferably, the bonding layer is obtained by coagulating a bonding agent, and the bonding agent consists of the following substances in percentage by mass:

30-50% of vinyl polysiloxane;

5-10% of water-based silicone-acrylic resin;

5-10% of epoxy modified organic silicon resin;

10-20% of polyurethane modified organic silicon resin;

10-30% of filler.

By adopting the technical scheme, the filler is an indispensable part of the resin film-forming material, the bonding layer prepared from the mixed resin combined by the formula can be well bonded with the leather layer on the one hand, and can be well bonded with the coating layer made of the silica gel material on the other hand, the good bonding property with the silica gel layer is mainly reflected in the phenomenon of silicon transfer existing on two-layer interfaces, and the silicon transfer phenomenon mainly refers to the phenomenon that the silicon oxygen bond of the silica gel layer is similar to the silicon oxygen bond of the bonding layer and interpenetration occurs. The resin material has good film forming property on leather, and the epoxy modified organic silicon resin is used for improving the adhesive force, so that the adhesive layer can be well adhered with a leather layer.

Preferably, the filler is one of natural crystalline silica, natural amorphous silica, kaolin or diatomaceous earth.

By adopting the technical scheme, the filler is of a type with high silicon content, and the silicon transfer phenomenon can be accelerated.

Aiming at the defects in the prior art, the invention also aims to provide the preparation method of the high-flame-retardant leather, which is simple and feasible, and the obtained leather has better flame-retardant property.

The technical purpose of the invention is realized by the following technical scheme, and the preparation method of the high flame-retardant leather comprises the following steps:

s1, preparing methyl vinyl silicone oil;

s2 preparation of crude rubber by using the methyl vinyl silicone oil obtained in S1;

s3 preparing a coating layer silica gel by using the raw rubber obtained in S2;

s4, preparing a binder;

s5, coating the binder obtained in the step S4 on the base material layer to form a bonding layer, heating to 60 ℃, cooling to 40 ℃ after 15min when the strength of the bonding layer reaches 30%, coating silica gel on the binder layer to form a silica gel layer, heating to 95 ℃, and after 1, completely molding the bonding layer and the silica gel layer.

By adopting the technical scheme, after the heating is carried out to 60 ℃ for 15-20min, the adhesive is not completely cured to form a film, the silica gel is coated at the moment, so that the adhesive and the silica gel can be better bonded together, the silica gel is coated at 40 ℃, the operation is facilitated, the film forming process of the adhesive is not interrupted, and finally, the heating is carried out for 1-1.5h at 95-100 ℃, so that the silica gel and the adhesive can be cured and can be better bonded together in the curing process.

Preferably, the synthesis of the methyl vinyl silicone oil comprises the following process steps:

step 1, mixing octamethylcyclotetrasiloxane and dimethyl siloxane mixed ring body, and dehydrating at 75 ℃ and under the vacuum degree of-0.09 Mpa to-0.12 Mpa;

step 2, adding a vinyl double-end socket and an alkali glue, reacting for 1h at 100 ℃, and then reacting for 3h at 110-;

step 3, cooling to 95-100 ℃, adding the dimethyl silicone oil, and then reacting for 2.5h at the temperature of 120-;

and 4, reducing the temperature for 20min at 170 ℃ under the vacuum condition of minus 0.08MPa to minus 0.1MPa, and then reducing the temperature for 10min at 200 ℃ under the vacuum condition of minus 0.09MPa to minus 0.11 MPa.

By adopting the technical scheme, the methyl vinyl silicone oil is an important material in the silica gel material coating layer, and the performance of the methyl vinyl silicone oil directly influences various performances of the coating layer, so that the methyl vinyl silicone oil prepared by the method has proper performances in various aspects and can meet the requirement of high-flame-retardant leather.

In conclusion, the invention has the following beneficial effects:

firstly, a novel high-flame-retardant leather research and development idea is provided, and the obtained high-flame-retardant leather can enrich the types of high-flame-retardant leather in the market;

secondly, the provided high-flame-retardant leather preparation method is simple and easy to implement, and can be suitable for industrialized leather production;

thirdly, the silica gel is adopted as the finishing agent, and the leather can obtain better flame retardant property without using a flame retardant.

Detailed Description

The present invention will be described in detail with reference to examples.

Example 1

A high flame-retardant leather comprises a coating layer, a bonding layer and a leather layer which are sequentially arranged from outside to inside, wherein the coating layer is made of a silica gel material. The thickness of the coating layer is 0.15, the thickness of the bonding layer is 0.15mm, and the thickness of the leather layer is 0.4 mm.

Wherein, the silica gel material is prepared by reacting hydrogen-containing silicone oil, a platinum catalyst, a pigment and raw rubber. Wherein the crude rubber is prepared by the reaction of fumed silica, a silane coupling agent, a platinum catalyst and methyl vinyl silicone oil. The methyl vinyl silicone oil is prepared by reacting octamethylcyclotetrasiloxane, a dimethyl siloxane mixed ring body, a vinyl double-end socket, alkali glue and dimethyl silicone oil, wherein the content of tetramethyl divinyl disiloxane in the vinyl double-end socket is 50%, the viscosity of the dimethyl silicone oil is 800-1200cps, and the viscosity of the obtained methyl vinyl silicone oil is 5000-8000 cps.

Wherein, the bonding layer is obtained by condensing a binder, and the binder consists of the following substances: vinyl polysiloxane, waterborne silicone-acrylate resin, epoxy modified silicone resin, polyurethane modified silicone resin and filler.

Wherein, the leather layer adopts superfine fiber PU synthetic leather.

The high flame retardant leather of example 1 was prepared using the following procedure:

s1 preparation of methyl vinyl silicone oil.

S2 preparation of crude rubber by using the methyl vinyl silicone oil obtained in S1; adding methyl vinyl silicone oil and gas phase silicon dioxide at 65 ℃, stirring and dispersing uniformly, adding a silane coupling agent and a platinum catalyst, heating to 75 ℃, stirring and reacting for 1h to obtain the crude rubber.

S3 preparing a coating layer silica gel by using the raw rubber obtained in S2; adding raw rubber pigment at 65 deg.C, stirring, adding hydrogen-containing silicone oil, heating to 80 deg.C, adding platinum catalyst, and reacting under stirring for 45min to obtain the final product.

S4, preparing a binder; sequentially adding waterborne silicone-acrylate resin, epoxy modified organic silicon resin, polyurethane modified organic silicon resin and filler at 25 ℃, stirring at 2000r/min for 10min, adding vinyl polysiloxane at 30 ℃, and stirring at 200r/min for 5min to obtain the epoxy modified silicone-acrylate modified silicone modified polyurethane modified silicone modified polyurethane.

S5, coating the binder obtained in S4 on a base material layer to form a bonding layer, heating to 60 ℃, cooling to 40 ℃ after 15min until the strength of the bonding layer reaches 30%, coating silica gel on the binder layer to form a silica gel layer, heating to 95 ℃, and after 1, completely molding the bonding layer and the silica gel layer.

In example 1, the synthesis of methyl vinyl silicone oil comprises the following process steps:

step 1, mixing octamethylcyclotetrasiloxane and dimethyl siloxane mixed ring body, and dehydrating at 75 ℃ and under the vacuum degree of-0.09 Mpa to-0.12 Mpa;

step 2, adding a vinyl double-end socket and an alkali glue, reacting for 1h at 100 ℃, and then reacting for 3h at 110-;

step 3, cooling to 95-100 ℃, adding the dimethyl silicone oil, and then reacting for 2.5h at the temperature of 120-;

and 4, reducing the temperature for 20min at 170 ℃ under the vacuum condition of minus 0.08MPa to minus 0.1MPa, and then reducing the temperature for 10min at 200 ℃ under the vacuum condition of minus 0.09MPa to minus 0.11 MPa.

Examples 2 to 4 were prepared in substantially the same manner as in example 1, except that the amount of the added material was different.

The following table shows the amounts of the various materials added in the preparation of the silica gel materials of examples 1-4

Item	Example 1	Example 2	Example 3	Example 4
					Hydrogen-containing Silicone oil (%)	10	25	15	20
Platinum catalyst (%)	0.7	0.6	1	0.8
					Colorant (%)	1	2	2	1
Crude rubber (%)	88.3	72.4	82	78.2

The following table shows the amounts of the materials added in the preparation of raw rubber in examples 1 to 4

Item	Example 1	Example 2	Example 3	Example 4
					Fumed silica (%)	25	30	28	26
Silane coupling agent (%)	8	7	6	8
					Platinum catalyst (%)	0.8	1	0.7	0.6
Methyl vinyl Silicone oil (%)	66.2	62	65.3	65.4

The following table shows the content of methyl vinyl silicone oil in examples 1 to 4

Item	Example 1	Example 2	Example 3	Example 4
					Dimethylsiloxane Mixed Ring body (%)	8	10	12	15
Vinyl double head (%)	5	10	15	12
					Alkali glue (%)	2	2	1	2
Dimethylsilicone oil (%)	5	5	4	5
					Octamethylcyclotetrasiloxane (%)	80	73	68	66

The fire-protection grades of the above embodiments all reach the fire-protection standard of B1.

The above are only preferred embodiments of the present invention, and the scope of the present invention is not limited to the above examples, and all technical solutions that fall under the spirit of the present invention belong to the scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.

Claims (5)

1. A high flame-retardant leather is characterized in that: the leather coating comprises a coating layer, a bonding layer and a leather layer which are arranged from outside to inside in sequence, wherein the coating layer is made of a silica gel material;

the silica gel material of the coating layer is prepared from the following components in percentage by mass:

10-25% of hydrogen-containing silicone oil;

0.6-1% of platinum catalyst;

1-2% of pigment;

the balance of raw rubber;

the raw rubber is prepared from the following components in percentage by mass:

25-30% of fumed silica;

6-8% of a silane coupling agent;

0.6-1% of platinum catalyst;

the balance of methyl vinyl silicone oil;

the methyl vinyl silicone oil is prepared from the following substances in percentage by mass:

8-15% of dimethyl siloxane mixed ring body;

5-15% of vinyl double end enclosure;

1-2% of alkali glue;

3-5% of dimethyl silicone oil;

octamethylcyclotetrasiloxane balance;

in the vinyl double-end socket, the content of tetramethyl divinyl disiloxane is 50%, the viscosity of the dimethyl silicone oil is 800-1200cps, and the viscosity of the obtained methyl vinyl silicone oil is 5000-8000 cps;

the thickness of the coating layer is 0.15mm, the thickness of the bonding layer is 0.15mm, and the thickness of the leather layer is 0.4 mm;

the bonding layer is obtained by coagulating a bonding agent, and the bonding agent consists of the following substances in percentage by mass:

30-50% of vinyl polysiloxane;

5-10% of water-based silicone-acrylic resin;

5-10% of epoxy modified organic silicon resin;

10-20% of polyurethane modified organic silicon resin;

10-30% of filler.

2. The high flame-retardant leather according to claim 1, wherein: the leather layer adopts superfine fiber PU synthetic leather.

3. The high flame-retardant leather according to claim 1, wherein: the filler is one of natural crystalline silica, natural amorphous silica, kaolin or diatomaceous earth.

4. The method for preparing the high flame-retardant leather according to any one of claims 1 to 3, which is characterized by comprising the following steps:

s1, preparing methyl vinyl silicone oil;

s2 preparation of crude rubber by using the methyl vinyl silicone oil obtained in S1;

s3 preparing a coating layer silica gel by using the raw rubber obtained in S2;

s4, preparing a binder;

s5, coating the binder obtained in S4 on the base material layer to form a bonding layer, heating to 60 ℃, cooling to 40 ℃ after 15min until the strength of the bonding layer reaches 30%, coating silica gel on the bonding layer to form a silica gel layer, and heating to 95 ℃ to completely mold the bonding layer and the silica gel layer.

5. The preparation method of the high flame-retardant leather according to claim 4, wherein the synthesis of the methyl vinyl silicone oil comprises the following process steps:

step 1, mixing octamethylcyclotetrasiloxane and dimethyl siloxane mixed ring body, and dehydrating at 75 ℃ and under the vacuum degree of-0.09 Mpa to-0.12 Mpa;

step 2, adding a vinyl double-end socket and an alkali glue, reacting for 1h at 100 ℃, and then reacting for 3h at 110-;

step 3, cooling to 95-100 ℃, adding the dimethyl silicone oil, and then reacting for 2.5h at the temperature of 120-;

and 4, reducing the temperature at 170 ℃ under the vacuum condition of minus 0.08MPa to minus 0.1MPa for 20min, and then reducing the temperature at 200 ℃ under the vacuum condition of minus 0.09MPa to minus 0.11MPa for 10 min.