CN113492001A

CN113492001A - Odor adsorbent and preparation method thereof, adhesive system and application thereof, aldehyde-free shaving board and preparation method thereof

Info

Publication number: CN113492001A
Application number: CN202010261331.6A
Authority: CN
Inventors: 孙卫华; 涂松; 李厚义; 张梓军; 王向硕; 范丽颖; 孙鹏; 胡兵波; 辛波
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2020-04-03
Filing date: 2020-04-03
Publication date: 2021-10-12
Anticipated expiration: 2040-04-03
Also published as: CN113492001B

Abstract

The invention provides an odor adsorbent and a preparation method thereof. The core-shell composite material has a core-shell structure, wherein the shell layer material is a thermoplastic material with a melting point/softening point of 40-120 ℃, and the core layer material is a powdery porous material or a two-dimensional layered material; the preparation method comprises the following steps: (1) performing glow plasma irradiation treatment on the nuclear layer material to obtain a modified nuclear layer material; (2) heating and melting the shell layer material, and adding the modified core layer material to obtain a precursor with a core-shell structure; (3) and (4) carrying out spray cooling on the precursor with the core-shell structure, and screening to obtain the odor adsorbent. Also provided are a binder system for reducing odor of an aldehyde-free particle board and use thereof, and a method for preparing a low-odor aldehyde-free particle board and a low-odor aldehyde-free particle board using the same; the binder system includes the aforementioned odor adsorbent. The odor adsorbent and the adhesive system thereof are easy to store, have strong and stable adsorption capacity, can reduce the odor grade of the formaldehyde-free shaving board and improve the performance of the formaldehyde-free shaving board; the preparation method is simple.

Description

Odor adsorbent and preparation method thereof, adhesive system and application thereof, aldehyde-free shaving board and preparation method thereof

Technical Field

The invention belongs to the field of adhesive systems for artificial boards and processing, and particularly relates to an odor adsorbent, a preparation method of the odor adsorbent, an adhesive system, application of the adhesive system, an aldehyde-free shaving board and a preparation method of the aldehyde-free shaving board.

Background

The technology of using wood or other non-wood plants as raw material, separating into particles, needle-shaped or sheet-shaped shavings, fibers and other units by mechanical processing, applying adhesive or other additives, and hot-pressing to make into the board has developed rapidly in recent years. The traditional artificial board products mainly comprise three board types of plywood, shaving board and fiber board; the extension products or deep processing products can reach hundreds of types. The artificial board is the beginning of the modernization of wood reprocessing, extends from changing the shape of wood to changing the performance of wood, and is a product of the modern industrial progress. The artificial board can improve the utilization rate of wood and save forest resources, and 1 cubic meter of artificial board can replace 3-5 cubic meters of log.

The urea-formaldehyde resin adhesive, the phenolic resin adhesive and the melamine resin adhesive used in the field of traditional artificial boards all generate formaldehyde in the use process of the boards, which is harmful to human health and has certain pungent smell.

The isocyanate does not contain a formaldehyde component, and is green and environment-friendly. The board prepared by the isocyanate adhesive has better physical and mechanical properties, because most of the functional group-NCO in the isocyanate reacts with water in the wood or non-wood plant raw materials at high temperature of hot pressing to generate products such as urea (-NH-CO-NH-) and biuret (-NH-CO-N-CO-NH-) which have strong cementing effect with the raw material units. The whole reaction process has no harmful substances, and the problem of formaldehyde release can be solved.

However, the end-users of the aldehyde-free boards made with isocyanate still feedback that the boards have a certain odor, and since most people do not know formaldehyde, once smelling the board odor, it is considered that there is formaldehyde release, and the actual odor may be the odor volatilized from some extracted chemical components of the wood itself, the odor generated when substances such as starch and sugars in the wood are metabolized or decomposed by microorganisms parasitizing in the wood, and the odor generated by the degradation of the wood during the processing. It has been found that these odorous substances are mainly aromatic compounds (1, 3-dimethylbenzene, etc.), ester compounds (butyl acetate, etc.) and aldehyde-ketone compounds (hexanal, etc.). These odorous substances make the panel with odor a poor quality one to be perceived by the subjective consciousness of the ordinary people. Therefore, the misunderstanding can be avoided only by fundamentally eliminating or reducing the odor of the plate, and the popularization and the application of the high-quality formaldehyde-free plate are facilitated.

CN 110696140a discloses a production method of low-odor veneer particle board, specifically reporting that the odor of the board is reduced by adding tea leaves, orange peel powder and slow-release odor-absorbing capsules into wood raw materials; CN 106945145A discloses a production process of a low-odor environment-friendly shaving board, which promotes odor emission by optimizing the shape of shaving, changing the tissue structure of the shaving board, reduces odor sources by using high-quality raw materials, and effectively reduces the odor grade of the board; CN 105313202a discloses a method for removing smell of redwood, which uses saturated steam to treat wood to remove smell of wood, but causes partial degradation of hemicellulose in the wood; CN 1364682a discloses a deodorization treatment method of euonymus mate wood, which is to soak wood with sodium hydroxide solution, ammonia water solution and ethanol solution at normal temperature for deodorization, so that lower fatty acid in the wood reacts with the above substances to generate tasteless salt or ester with apple fragrance; CN 103624852a discloses a method for deodorizing water wood flower and pear wood, which utilizes low-temperature plasma treatment to increase the escape rate of wood odor molecules and uses ozone to oxidize and digest odor substances. However, changing the shavings morphology and the plate texture results in major variations in the production process; wood pretreatment can result in different degrees of wood degradation, which is not conducive to improving the performance of the board.

Therefore, there is a need for a binder system for reducing the odor of aldehyde-free particle boards, so as to reduce the odor of aldehyde-free particle boards, improve the performance of aldehyde-free particle boards, and expand the application of aldehyde-free particle boards.

Disclosure of Invention

The first purpose of the invention is to provide an odor adsorbent, which has strong adsorption effect on odor substance molecules in a base material used for preparing an aldehyde-free shaving board and can reduce the odor grade of the aldehyde-free shaving board;

the second purpose of the invention is to provide a preparation method of the odor adsorbent, the preparation method is simple and easy to operate, and the prepared odor adsorbent can reduce the odor grade of an aldehyde-free shaving board when being used for preparing the aldehyde-free shaving board;

a third object of the present invention is to provide a binder system for reducing the odor of aldehyde-free particle board, which binder system, when used for the preparation of aldehyde-free particle board, is capable of reducing the odor level of aldehyde-free particle board;

a fourth object of the present invention is to provide the use of the aforementioned binder system in the preparation of low odor aldehyde-free particle board;

a fifth object of the present invention is to provide a method for preparing low odor aldehyde-free particle board using the aforementioned binder system; the preparation method is simple and easy to operate, and the low-odor formaldehyde-free shaving board can be prepared;

the sixth purpose of the invention is to provide a low-odor aldehyde-free particle board prepared by the preparation method.

In order to realize the first purpose of the invention, the following technical scheme is adopted:

an odor adsorbent has a core-shell structure, and in the core-shell structure of the odor adsorbent, a shell layer material is a thermoplastic material with a melting point/softening point of 40-120 ℃, such as POE (polyolefin elastomer), PEG (polyethylene glycol), PA (polyamide), EVA (ethylene-vinyl acetate copolymer) and paraffin wax, or a combination of any one or more of the above materials; the nuclear layer material is a powdery porous material (such as activated carbon and a molecular sieve, preferably a 13X aluminosilicate molecular sieve) or a two-dimensional layered material (such as molybdenum sulfide, boron nitride, graphite and MXene two-dimensional crystals, preferably MXene two-dimensional crystals).

The common odor adsorbent does not have a core-shell structure, is only equivalent to the core layer material in the invention, such as activated carbon, molecular sieve and the like, is not easy to store, and is easy to adsorb odor substance molecules in the air to pollute in the storage process, thereby reducing the adsorption capacity of the odor adsorbent; and because the particle size of the core layer material is smaller, when the core layer material is directly used for preparing the low-odor formaldehyde-free shaving board, the core layer material is easy to settle to the bottom when being mixed with a base material (such as wood shavings), so that the distribution of the core layer material in the shaving board is uneven, the adsorption capacity on odor substance molecules is influenced, and the odor elimination effect is influenced. The odor adsorbent has a core-shell structure, so that on one hand, the odor adsorbent is easy to store, and in the storage process, the shell material can protect the core-shell material from being polluted, so that the actual adsorption capacity of the odor adsorbent is prevented from being reduced in the storage process, and the storage time of the odor adsorbent is prolonged; in addition, as the core-shell layer material is wrapped outside the core-shell layer material to form the core-shell structure, the particle size of the odor adsorbent can be improved, so that when the odor adsorbent is used for preparing the low-odor aldehyde-free shaving board, the odor adsorbent can be effectively prevented from settling, the distribution uniformity of the odor adsorbent is improved, the adsorption capacity of the odor adsorbent on odor substance molecules in a base material (such as wood shavings) is improved, and the odor elimination effect of the odor adsorbent on the prepared aldehyde-free shaving board is further improved.

Preferably, the shell material is a hot melt adhesive with a melting point of 45-100 ℃ (such as 50 ℃, 60 ℃, 70 ℃, 80 ℃ and 90 ℃), such as any one or a combination of POE hot melt adhesive, PEG hot melt adhesive, PA hot melt adhesive and EVA hot melt adhesive; preferably, the shell material is EVA hot melt adhesive with the melting point of 45-85 ℃, such as 50 ℃, 60 ℃, 70 ℃ and 80 ℃.

When the shell material is hot melt adhesive, when the odor adsorbent is used for preparing the low-odor aldehyde-free shaving board, the shell material is melted, and then the core material can be released to adsorb odor substance molecules, and can also play a role in bonding, so that the odor of the aldehyde-free shaving board is reduced, and the strength of the aldehyde-free shaving board can be improved.

The powder porous material and the two-dimensional layered material have an adsorption function as a core layer material, and the adsorption capacity of the powder porous material and the two-dimensional layered material is related to the pore size, the interlayer spacing and the types and the number of surface groups; if the pore diameter or the interlayer spacing is too small, the odor substance molecules cannot enter, and the adsorption effect cannot be achieved; if the pore size or the interlayer distance is too large, the molecules of the odorant are easily desorbed. The artificial board has complicated odor sources and large molecular size difference of odor substances. The MXene two-dimensional crystal is a novel two-dimensional layered transition metal carbide or carbonitride nano material with a graphene-like structure, and is obtained by etching off an element A in MAX-phase ceramics (M is a transition metal element, A is an IIIA or IVA group element, and X is carbon or nitrogen element) of a precursor by a chemical liquid phase method, wherein the chemical formula of the MXene two-dimensional crystal is Mn +1Xn (n is 1, 2 and 3, M is a transition metal element, and X is carbon or nitrogen element). The interlayer spacing of MXene two-dimensional crystal is 2.0-2.5nm, and can adsorb most aromatic compounds (1, 3-dimethylbenzene, etc.), ester compounds (butyl acetate, etc.) and aldehyde ketone compounds (hexanal, etc.). Therefore, in one embodiment, the core layer material is MXene two-dimensional crystals, and preferably the core layer material is MXene two-dimensional crystals with the particle size of 200-325 meshes, so as to improve the adsorption effect of the MXene two-dimensional crystals on odor substance molecules in a base material used for preparing the aldehyde-free shaving board.

Preferably, the particle size of the odor adsorbent is 50 to 60 mesh, so that when the odor adsorbent is used for preparing a low-odor aldehyde-free particle board, the distribution uniformity of the odor adsorbent can be improved, the odor adsorbent is prevented from settling, the adsorption capacity of the odor adsorbent on molecules of odor substances is improved, and the odor is effectively eliminated.

In order to achieve the second purpose of the invention, the following technical scheme is adopted:

a method of making an odor adsorbent as described above, comprising the steps of:

(1) the nuclear layer material is laid on a tray and then is subjected to glow plasma irradiation treatment to be activated, so that a modified nuclear layer material is obtained;

(2) heating and melting the shell layer material, adding the modified core layer material obtained in the step (1) into the shell layer material, and uniformly stirring to obtain a precursor with a core-shell structure;

(3) and (3) carrying out spray cooling on the precursor with the core-shell structure obtained in the step (2), and screening to obtain the odor adsorbent with the core-shell structure.

The preparation method of the odor adsorbent is simple and easy to operate, and the odor adsorbent with the core-shell structure is easy to obtain.

In the step (1), the core layer material is activated by glow plasma irradiation treatment, so that the number of polar groups on the surface of the core layer material is effectively increased, and the adsorption capacity of the core layer material on polar odor substance molecules is improved. In one embodiment, in the step (1), the irradiation atmosphere is an air atmosphere; the irradiation environment preferably has a relative humidity of 40-70%, such as 45%, 50%, 55%, 60% and 65%, so that the hydroxyl groups in the water are grafted to the core layer material to activate it, thereby increasing its adsorption effect on the odorant molecules. Preferably, in the step (1), the irradiation voltage is 50-150V, such as 60V, 70V, 80V, 90V, 100V, 110V, 120V, 130V and 140V; irradiation current is 0.5-2.5A, such as 1.0A, 1.5A and 2.0A; the irradiation time is 1-10min, such as 2min, 3min, 4min, 5min, 6min, 7min, 8min and 9min, so as to effectively activate the nuclear layer material. Preferably, in the step (1), the electrode is located above the nuclear layer material during the irradiation treatment, and the distance from the nuclear layer material is 0.5-5cm, such as 1cm, 1.5cm, 2cm, 2.5cm, 3cm, 3.5cm, 4 cm and 4.5 cm. In one embodiment, in step (1), the tiling thickness is 0.8-1 mm, such as 0.9 mm.

Preferably, in the step (2), the mass ratio of the shell layer material to the modified core layer material is (1-1.25):1, such as 1.05:1, 1.1:1, 1.15:1 and 1.2: 1. The mass of the core layer material before and after modification is not changed greatly and can be almost ignored, therefore, the mass ratio of the shell layer material to the modified core layer material can be calculated according to the mass ratio of the shell layer material to the core layer material, namely the mass ratio of the shell layer material to the core layer material is (1-1.25):1, such as 1.05:1, 1.1:1, 1.15:1 and 1.2: 1. At the moment, the shell layer material can completely wrap the modified core layer material to form a core-shell structure, and the proportion of the modified core layer material in the odor adsorbent can be increased as much as possible, so that the adsorption effect of the odor adsorbent on odor substance molecules is improved.

When the heating temperature of the shell material is too high, on one hand, the shell material can be decomposed or volatilized to be lost; on the other hand, the viscosity of the melted/softened shell layer material is also reduced, so that when the modified core layer material is added and mixed, the modified core layer material is not easy to suspend and is easy to sink to the bottom layer of the melted/softened shell layer material, and the modified core layer material is not uniformly distributed in the shell layer material, so that the uniformity of the prepared core-shell structure precursor is influenced, for example, the proportion of the modified core layer material in the upper core-shell structure precursor is smaller, the proportion of the modified core layer material in the lower core-shell structure precursor is larger, and the uniformity of the prepared odor adsorbent is influenced; moreover, the precursor with the core-shell structure is not easy to condense when the heating temperature is too high for subsequent spray cooling. If the heating temperature of the shell material is too low, it may not completely melt/soften, which may adversely affect the coating of the core material. Preferably, in the step (2), the shell material is heated to a temperature 5 to 20 ℃, preferably 10 to 15 ℃, such as 11 ℃, 12 ℃, 13 ℃ and 14 ℃ above the melting/softening point of the shell material.

In one embodiment, in the step (2), the stirring speed is 600-.

Preferably, in the step (3), the spray cooling is to spray the core-shell structure precursor in an air spraying manner so that the core-shell structure precursor meets condensation; preferably, the air spraying mode is air atomization.

The air spraying is that the air flow of compressed air flows through the nozzle hole of the spray gun to form negative pressure, and the negative pressure causes the material to be sucked from the suction pipe and sprayed out through the nozzle to form spray.

In order to achieve the third object of the present invention, the following technical solutions are adopted:

an adhesive system for reducing odor of aldehyde-free particle board comprising a plurality of functional isocyanates and an odor absorbent disposed in spaced apart relation; wherein the odor adsorbent is the odor adsorbent or the odor adsorbent prepared according to the preparation method.

The odor adsorbent of the adhesive system has a core-shell structure, so that the odor adsorbent can be wrapped by a shell material when placed, and the modified core layer material with the inner layer having adsorption capacity can be prevented from adsorbing odor substance molecules in the air to be polluted or invalid, so that the storage time of the odor adsorbent is prolonged, and the stability and the high efficiency of the adsorption capacity of the odor adsorbent are ensured.

The adhesive system for reducing the odor of the aldehyde-free shaving board can effectively adsorb odor substance molecules in a base material used for preparing the aldehyde-free shaving board by using the odor adsorbent, reduce the odor grade of the aldehyde-free shaving board, improve the performance of the aldehyde-free shaving board, and expand the popularization and application of the aldehyde-free shaving board

It is understood by those skilled in the art that the multifunctional isocyanates are common materials in the art for preparing adhesive systems. In one embodiment, the polyfunctional isocyanate is any one or combination of aromatic, aliphatic and araliphatic polyisocyanates.

The isocyanate refers to a compound containing an isocyanate (-NCO) group in the structure and can be used as an adhesive. Polyfunctional isocyanates are classified into three major classes, based on the structural characteristics of the isocyanate groups attached to carbon atoms, namely aromatic polyisocyanates (such as toluene diisocyanate, i.e., TDI), aliphatic polyisocyanates (such as hexamethylene diisocyanate, i.e., HDI), and araliphatic polyisocyanates (i.e., aliphatic hydrocarbon groups, often polymethylene groups, such as xylylene diisocyanate, i.e., XDI, are interposed between an aryl group and a plurality of isocyanate groups), and these three major classes are applicable to the present invention. Among them, aromatic polyisocyanates such as Toluene Diisocyanate (TDI), diphenylmethane diisocyanate (MDI) and polymeric diphenylmethane diisocyanate (also known as polymeric MDI or PMDI) are relatively inexpensive. Thus, in a preferred embodiment, the polyfunctional isocyanate is preferably an aromatic polyisocyanate, more preferably a combination of any one or more of toluene diisocyanate, diphenylmethane diisocyanate and polymethylene polyphenyl polyisocyanates.

Wherein the polymethylene polyphenyl polyisocyanate (i.e., polymeric MDI or PMDI) is a mixture of polyisocyanates of different functionalities and having the formula:

diphenylmethane diisocyanate (i.e. MDI) in which n-0 represents about 40% by weight of the mixture, and the MDI structure is predominantly 4,4 '-MDI, possibly containing a minor amount of the 2, 4' -MDI isomer. The remainder of the PMDI is a low-polymerization polyisocyanate of 3-5 functionality. Regardless of the adjustment of the ratio of the two structures in the MDI, PMDI having an-NCO content in the range of 30 to 34% by weight is applicable to the present invention. The PMDI has an average molecular weight of 320-420, an average functionality of 2.5-3.0 and a viscosity of about 150-250cP at 25 ℃. In a preferred embodiment, the polyfunctional isocyanate is a polymethylene polyphenyl polyisocyanate having a functionality of 2.6 to 2.8 and a viscosity of 150-250cP at 25 ℃.

Modified products based on PMDI or TDI or MDI or combinations thereof, including but not limited to polyether modification and polyester modification, can also be used in the present invention as the starting polyfunctional isocyanate in the present invention, provided that the-NCO content is in the range of 20 to 34% by weight.

To achieve the fourth object of the present invention, there is also provided the use of the aforementioned adhesive system in the preparation of low odor aldehyde-free particle board.

In order to achieve the fifth object of the present invention, the following technical solutions are adopted:

a method of making a low odor, aldehyde-free particle board utilizing the foregoing binder system, comprising the steps of:

(1) uniformly mixing the odor adsorbent in the adhesive system and the surface layer base material according to the mass ratio of (0.01-0.05) to 1 (such as 0.02:1, 0.03:1 and 0.04:1) to obtain a surface layer mixed material;

(2) spraying the polyfunctional isocyanate in the adhesive system into the surface layer mixed material obtained in the step (1) while stirring until the polyfunctional isocyanate is uniformly mixed, so as to obtain a pretreated surface layer substrate;

(3) uniformly mixing the odor adsorbent in the adhesive system with a core layer base material according to the mass ratio of (0.01-0.05):1 to obtain a core layer mixed material;

(4) spraying the polyfunctional isocyanate in the adhesive system into the core layer mixed material obtained in the step (3) while stirring until the polyfunctional isocyanate is uniformly mixed, so as to obtain a pretreated core layer substrate;

(5) and (3) paving the pretreated surface layer base material obtained in the step (2) and the pretreated core layer base material obtained in the step (4) according to the surface layer-core layer-surface layer in sequence to obtain a plate blank, and performing prepressing and hot pressing procedures on the obtained plate blank in sequence to obtain the low-odor formaldehyde-free shaving board.

It is understood by those skilled in the art that in steps (1) and (3), the mixing may be performed using mixing means commonly used in the art, and in one embodiment, the mixing is performed using mechanical agitation.

Those skilled in the art understand that when the pretreated surface substrate is obtained, the odor adsorbent can be mixed with the surface substrate, and the multifunctional isocyanate is sprayed into the odor adsorbent while stirring, so that the three are uniformly mixed to obtain the pretreated surface substrate; when the pretreated core layer base material is obtained, the odor adsorbent and the core layer base material can be mixed, and the multifunctional isocyanate is sprayed into the odor adsorbent and the core layer base material while stirring, until the three are uniformly mixed, so that the pretreated core layer base material is obtained.

Preferably, in the obtained low-odor aldehyde-free particle board, the mass ratio of the surface layer substrate to the core layer substrate is (0.4-1):1, such as 0.5:1, 0.6:1, 0.7:1, 0.8:1 and 0.9: 1.

Preferably, in the step (1), the surface substrate is wood shavings and/or non-wood plant fiber shavings, preferably wood shavings; in the step (3), the core substrate is wood shavings and/or non-wood plant fiber shavings, preferably wood shavings.

Those skilled in the art will appreciate that wood strands include strands derived from the processing of any one or more of the conventional woods such as poplar, pine, eucalyptus, and the like; the non-wood plant fiber shavings comprise shavings obtained by processing any one or more of non-wood plant fibers such as straws, wheat straws, reeds, cotton stalks, hemp stalks, corn stalks, bagasse and the like; those skilled in the art will appreciate that wood strands derived from wood can be processed in ways including shredding, flaking, chipping, and the like; the processing method of obtaining the non-wood plant fiber shavings from the non-wood plant fibers includes cutting, sorting (i.e., taking out the leaves and the cores), crushing, grinding, and the like.

Preferably, in the step (1), the surface base material has a water content of 16 to 20 wt%, such as 17 wt%, 18 wt% and 19 wt%, and a particle size of 0.1 to 1mm, such as 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm and 0.9 mm; in the step (3), the core substrate has a water content of 2 to 5 wt%, such as 3 wt% and 4 wt%, and a particle size of > 1mm, such as 2mm, 8mm and 15 mm.

Preferably, in the step (2), the spraying amount of the polyfunctional isocyanate is 3 to 4.5 wt%, such as 3.5 wt% and 4 wt%, of the surface layer substrate; in the step (4), the spraying amount of the polyfunctional isocyanate is 2.5 to 3.5 wt%, for example, 3 wt% of the core layer substrate.

Those skilled in the art will understand that in the steps (2) and (4), the spraying manner is a spraying manner commonly used in the art, such as one or more of a combination of a rotary atomization spraying manner, a high-pressure atomization spraying manner and an air spraying manner.

Those skilled in the art understand that in step (5), hot pressing is performed in a hot press; the slab needs to be pre-pressed before entering the hot press, so that the slab structure is relatively compact and maintains a certain thickness, then the slab enters the hot press, hot pressing treatment is carried out under the action of certain temperature and pressure, the slab is rapidly compressed, the adhesive is cured, good combination is formed among the shavings, and the slab is hot-pressed into a board with a certain density and thickness. The hot pressing temperature is 200 ℃ and 230 ℃, such as 210 ℃ and 220 ℃; in the hot pressing process, in order to discharge excessive water in the plate blank from the edge of the plate blank and prevent plate explosion, the hot pressing process is carried out in two sections, namely, the pressure of a high-pressure section is 2-2.5MPa, and the pressure of a low-pressure section is 0.7-1.2 MPa; the hot pressing time can be controlled to be 6-8s/mm according to the thickness of the plate, wherein the hot pressing time of the high-pressure section is about 1/3, and the hot pressing time of the low-pressure section is about 2/3.

To achieve the sixth object of the present invention, there is also provided a low-odor aldehyde-free particle board manufactured according to the foregoing manufacturing method. It is understood by those skilled in the art that the binder system used in the preparation of the low odor aldehyde-free particle board is the binder system described above, wherein the odor adsorbent is the odor adsorbent described above.

The "mesh number" of the present invention is the mesh number of the Taylor standard sieve.

The invention has the beneficial effects that:

(1) the odor adsorbent has a core-shell structure, so that the odor adsorbent is easy to store, and in the storage process, the shell material can protect the core layer material from being polluted, so that the actual adsorption capacity of the odor adsorbent is prevented from being reduced in the storage process, and the storage time of the odor adsorbent is prolonged; in addition, as the core-shell layer material is wrapped outside the core-shell layer material to form a core-shell structure, the particle size of the odor adsorbent can be improved, so that when the odor adsorbent is used for preparing the low-odor aldehyde-free shaving board, the odor adsorbent can be effectively prevented from settling, the distribution uniformity of the odor adsorbent is improved, the adsorption capacity of the odor adsorbent on odor substance molecules in a base material (wood shavings) is improved, and the odor elimination effect of the odor adsorbent on the prepared aldehyde-free shaving board is further improved; the hot melt adhesive is preferably used as a shell material to form a core-shell structure together with the odor adsorbent, so that when the low-odor aldehyde-free shaving board is prepared subsequently, the easy addition and good adsorption capacity of the odor adsorbent can be ensured, and the physical and mechanical properties of the odor aldehyde-free shaving board are improved;

(2) the preparation method of the odor adsorbent has simple process and easy operation, and the nuclear layer material is activated by glow plasma irradiation treatment, so that the number of polar groups on the surface of the nuclear layer material is effectively increased, and the adsorption capacity of the nuclear layer material on polar odor substance molecules is improved; the modified core-shell material is wrapped by the shell material to form a core-shell structure, so that the storage time of the prepared odor adsorbent is prolonged;

(3) according to the adhesive system for reducing the odor of the aldehyde-free shaving board, the odor adsorbent is utilized, so that odor substance molecules in a base material used for preparing the aldehyde-free shaving board can be effectively adsorbed, the odor grade of the aldehyde-free shaving board is reduced, the performance of the aldehyde-free shaving board is improved, and the popularization and application of the aldehyde-free shaving board are expanded;

(4) the adhesive system can be applied to preparing the low-odor aldehyde-free shaving board, can reduce the odor grade of the aldehyde-free shaving board, improves the quality of the aldehyde-free shaving board and obtains the low-odor aldehyde-free shaving board;

(5) the preparation method of the low-odor formaldehyde-free shaving board has simple process and easy operation; the solution for reducing the odor of the formaldehyde-free shaving board does not need to greatly change the production process, and does not have negative influence on the performance of the board;

(6) the low-odor formaldehyde-free shaving board disclosed by the invention is low in odor grade, good in performance and quality, and beneficial to expanding popularization and application, and the acceptance degree of common people on the formaldehyde-free shaving board is improved.

Detailed Description

The technical solution and the effects of the present invention are further described by the following specific examples. The following examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention. Simple modifications of the invention applying the inventive concept are within the scope of the invention as claimed.

The sources of the raw materials used in the following examples and comparative examples are as follows:

1. polyfunctional isocyanates

Polymethylene polyphenyl Polyisocyanate (PMDI): a functionality of about 2.7, a viscosity of 180-250cP at 25 deg.C, an NCO content of 30.5-32 wt%, Vanhua Chemicals group Ltd;

toluene Diisocyanate (TDI): 2, 4-mer content 67. + -.2 wt.%, 4, 4-mer content 33. + -.2 wt.%, freezing point 6-8 ℃ and viscosity 3cP at 25 ℃ and-NCO content 48 wt.%, Bosu chemical Co., Ltd. (Hungary);

2. surface layer substrate/core layer substrate

Substrate 1: surface layer wood shavings of eucalyptus, having a water content of 20 wt%, a particle size of 0.2-0.7mm, from Hebeihui Yinlu Wood Co;

base material 2: wheat straw surface layer shavings with water content of 16 wt% and particle size of 0.1-0.8mm, Wanhua cereal straw Board industry (Jingmen) Limited liability company;

base material 3: eucalyptus wood core layer wood shavings with water content of 2 wt% and particle size of 1-12mm, Hebeihui Yinlu Wood Co;

base material 4: shaving the reed core layer, wherein the water content is 5 wt%, the particle size is 2-15mm, and the coil brocade volume is young shoot of a reed ecological board industry Co., Ltd;

3. shell material

Semi-refined paraffin No. 58 with a melting point of 58 ℃ and Shijiazhuang Junsai chemical technology Co., Ltd;

EVA Hot melt adhesive, DuPont Elvax 40W, melting point 47 deg.C, Zhengqi plastics materials Co., Ltd, Dongguan city;

EVA Hot melt adhesive, DuPont Elvax 150, melting point 63 deg.C, Zhengqi plastics materials Co., Ltd., Dongguan city;

EVA hot melt adhesive, TAISOX EVA 7350M, melting point 84 deg.C, Taiwan Taiyi Industrial Co., Ltd;

POE hot melt adhesive, Dow 8003, with a softening point of 63 ℃, Shanghai Qirui plastics Co., Ltd;

4. core layer material

MXene two-dimensional crystal, Ti₃C₂200 mesh, Beijing Dingsheng brother science and technology Co., Ltd;

MXene two-dimensional crystal, Ti₃C₂60 mesh, Beijing Dingsheng brother science and technology Co., Ltd;

MXene two-dimensionalCrystals of Ti₂N, 200 mesh, Beijing Beike New materials science and technology Co;

MXene two-dimensional crystal, Nb₂C, 270 mesh, Beijing Beike New materials science and technology Co;

MXene two-dimensional crystal, V₂C, 325 mesh, Beijing Beike science and technology Co., Ltd;

activated carbon, ZZ-700, 200 mesh, Liyang, Jiangnan activated carbon plant;

active carbon, ZZ-767, 200 mesh, Liyang, Jiangnan active carbon factory;

13X aluminosilicate molecular sieves, 200 mesh, New molecular sieves, Inc., available in Shanghai.

The test method is as follows:

testing the mechanical property of the plate: testing the internal bonding strength, the elastic modulus and the static bending modulus of the plate according to a physical and chemical performance test method of GBT 17657-supplemented 2013 artificial boards and veneer artificial boards;

evaluation of odor grade of the plate: evaluating the odor grade of the plate according to a Q-SFYJJ 15-2015 household material odor detection method and technical requirements;

testing the release amount of the TVOC of the plate: testing the TVOC release amount of the board according to the technical requirements of the artificial board and the product thereof according to the HJ 571-2010 environmental label product.

Example 1(S1) preparation of odor adsorbent A1

(1) MXene two-dimensional crystal Ti with the grain diameter of 200 meshes is prepared in an environment with the relative humidity of 40 percent₃C₂The (nuclear layer material) is flatly paved on a tray, and the flatly paved thickness is 1 mm; then adjusting the height of the electrode to be positioned in the obtained tiled MXene two-dimensional crystal Ti₃C₂Performing air atmosphere glow plasma irradiation treatment on the position 1cm above the substrate to activate the position to obtain a modified nuclear layer material; wherein the irradiation voltage is 120V, the irradiation current is 1.0A, and the irradiation time is 2 min;

(2) heating EVA hot melt adhesive-DuPont Elvax 40W (shell material) to 57 ℃ for melting, adding the modified core layer material obtained in the step (1) into the EVA hot melt adhesive at a mass ratio of 1:1 (according to the mass ratio of the shell material to the core layer material), and stirring at a speed of 600r/min until the materials are uniformly mixed to obtain a precursor of a core-shell structure;

(3) and (3) carrying out spray cooling on the precursor with the core-shell structure obtained in the step (2) by using compressed air with the pressure of 5bar, and screening to obtain the odor adsorbent A1 with the core-shell structure and the particle size of 50-60 meshes.

Examples 2-8(S2-8) preparation of odor adsorbents A2-8

Odor adsorbent A2-8 was prepared according to the method of example 1, with the raw materials and amounts thereof, and the process conditions as shown in Table 1.

TABLE 1S 1-8 raw materials, their amounts and process conditions

Examples 9-16(S9-16) preparation of Low odor aldehyde-free particle Board B1-8

(1) Uniformly mixing an odor adsorbent in an adhesive system with a surface layer base material to obtain a surface layer mixed material;

(2) spraying polyfunctional isocyanate in an adhesive system into the surface layer mixed material obtained in the step (1) while stirring until the polyfunctional isocyanate is uniformly mixed, so as to obtain a pretreated surface layer substrate;

(3) uniformly mixing an odor adsorbent in the adhesive system with the core layer base material to obtain a core layer mixed material;

(4) spraying polyfunctional isocyanate in an adhesive system into the core layer mixed material obtained in the step (3) while stirring until the polyfunctional isocyanate is uniformly mixed, so as to obtain a pretreated core layer substrate;

(5) and (3) paving the pretreated surface layer base material obtained in the step (2) and the pretreated core layer base material obtained in the step (4) according to the surface layer-core layer-surface layer in sequence to obtain a plate blank, and performing pre-pressing and hot-pressing procedures on the obtained plate blank in sequence to obtain the low-odor formaldehyde-free shaving board B1-8.

TABLE 2S 9-16 raw materials, their amounts and process conditions

Comparative examples 1 to 7(D1-7) preparation of odor adsorbents A1 '-2' and aldehyde-free particle boards B1 '-7'

COMPARATIVE EXAMPLE 1(D1)

The same procedure as in example 9 was repeated except that no odor adsorbent was added, to obtain aldehyde-free particle board B1'.

COMPARATIVE EXAMPLE 2(D2)

In both the steps (1) and (3), only 200 mesh Ti was used₃C₂As an odor adsorbent, 5g of each was used, and the remainder was the same as in example 9, to obtain aldehyde-free chipboard B2'.

COMPARATIVE EXAMPLE 3(D3)

In both steps (1) and (3), the same procedure was followed as in example 14 except that 200 mesh ZZ-700 was used as the odor adsorbent in an amount of 25g, to obtain an aldehyde-free particle board B3'.

COMPARATIVE EXAMPLE 4(D4)

In both the steps (1) and (3), only 60-mesh Ti is used₃C₂As an odor adsorbent, 5g of each was used, and the remainder was the same as in example 9, to obtain aldehyde-free chipboard B4'.

COMPARATIVE EXAMPLE 5(D5)

The environmental relative humidity was changed to 30% only, and the rest was the same as in example 1, to obtain an odor adsorbent a 1';

the same as in example 9 except that the odor adsorbent in steps (1) and (3) was changed to a1 ', aldehyde-free particle board B5' was obtained.

COMPARATIVE EXAMPLE 6(D6)

The same procedure as in example 9 was repeated except that the odor adsorbent in steps (1) and (3) was changed to A1 'obtained in comparative example 5 in an amount of 7.5g, to obtain an aldehyde-free particle board B6'.

COMPARATIVE EXAMPLE 7(D7)

The ambient relative humidity was changed to 80% only, and the rest was the same as in example 1, to obtain an odor adsorbent a 2';

the same procedure as in example 9 was repeated except that the odor adsorbent in steps (1) and (3) was changed to A2 'in an amount of 10g, to obtain an aldehyde-free particle board B7'.

The test results of the mechanical properties, odor grade and TVOC release amount of the low-odor aldehyde-free shaving boards B1-8 obtained in examples 9-16 are shown in Table 3; the results of the tests on the mechanical properties, odor ratings, and TVOC emissions of the boards of the aldehyde-free particle boards B1 '-7' obtained in comparative examples 1-7 are shown in table 4.

Table 3B 1-8 test results of mechanical properties, odor grade, TVOC release amount of the sheet

Table 4B 1 '-7' testing results of mechanical property, odor grade and TVOC release amount of the plate

The results of example 9 and comparative example 1 show that the odor grade and TVOC release amount of the board can be effectively reduced by adding the odor adsorbent with the core-shell structure.

Comparison of the results of example 9 with comparative example 2 and comparative example 4, and example 14 with comparative example 3 shows that the odor adsorbent obtained by irradiating a two-dimensional material (MXene two-dimensional crystal) or a porous material with an air atmosphere glow plasma and constructing a core-shell structure has significantly improved adsorption performance compared to an odor adsorbent not irradiated with an air atmosphere glow plasma and constructed a core-shell structure.

Comparison of the results of example 9 and comparative examples 5 to 7 shows that the effect of the relative humidity on the improvement of the adsorption capacity of the obtained odor adsorbent by the irradiation of the air atmosphere glow plasma on the nuclear layer material is remarkable, and the adsorption capacity of the obtained odor adsorbent is greatly improved when the irradiation treatment of the air atmosphere glow plasma on the nuclear layer material is carried out within the relative humidity range of 40 to 70 percent.

Comparison of the results of examples 9-13 with examples 14-16 shows that MXene two-dimensional crystals have superior odor adsorption capacity to aldehyde-free particle boards over activated carbon and molecular sieves and are used in significantly reduced amounts.

A comparison of the results of example 9 and example 13 shows that the use of EVA hot melt adhesives further improves the bond strength of the resulting aldehyde-free particle board.

The results of the above examples and comparative examples show that the odor grade and TVOC release amount of the plate can be effectively reduced and the mechanical properties of the plate can be improved by adding the odor adsorbent with the core-shell structure.

Claims

1. The odor adsorbent is characterized by having a core-shell structure, wherein in the core-shell structure of the odor adsorbent, a shell layer material is a thermoplastic material with a melting point/softening point of 40-120 ℃, and a core layer material is a powdery porous material or a two-dimensional layered material.

2. The odor adsorbent of claim 1 wherein said shell material is a hot melt adhesive having a melting point of 45-100 ℃; preferably EVA hot melt adhesive with the melting point of 45-85 ℃;

preferably, the particle size of the odor adsorbent is 50 to 60 mesh.

3. A method of making an odor adsorbent as defined in claim 1 or 2, wherein said method comprises the steps of:

4. The method according to claim 3, wherein in the step (1), the irradiation voltage is 50 to 150V, the irradiation current is 0.5 to 2.5A, and the irradiation time is 1 to 10 min;

preferably, in the step (1), the irradiation atmosphere is an air atmosphere; further preferably, the relative humidity of the irradiation environment is 40-70%;

preferably, in the step (1), the electrode is located above the nuclear layer material and at a distance of 0.5-5cm from the nuclear layer material during irradiation treatment.

5. The method as claimed in claim 3 or 4, wherein in the step (2), the mass ratio of the shell layer material to the modified core layer material is (1-1.25): 1;

preferably, in the step (2), the shell material is heated to a temperature 5-20 ℃ higher than the melting/softening point thereof.

6. An adhesive system for reducing odor of aldehyde-free particle board, said adhesive system comprising a plurality of functional isocyanates and an odor absorbent disposed in spaced apart relation; wherein the odor adsorbent is the odor adsorbent of claim 1 or 2 or the odor adsorbent prepared by the method of any one of claims 3 to 5.

7. The adhesive system according to claim 6, wherein the polyfunctional isocyanate is any one or combination of aromatic, aliphatic and araliphatic polyisocyanates.

8. Use of the binder system according to claim 6 or 7 for the preparation of low odor aldehyde-free particle boards.

9. A process for preparing low odor aldehyde-free particle board using the binder system of claim 6 or 7, wherein said process comprises the steps of:

(1) uniformly mixing the odor adsorbent in the adhesive system with a surface layer base material according to the mass ratio of (0.01-0.05):1 to obtain a surface layer mixed material;

10. A low odor aldehyde-free particle board made according to the method of claim 9.