KR102565837B1 - Foam composition applied for inorganic chemical blowing agent with improved foaming efficiency - Google Patents

Abstract

The present invention relates to a foam composition using an inorganic chemical foaming agent with improved foaming efficiency, and more particularly, foaming that can increase the reaction rate by including citric acid, increase decomposition efficiency by including a co-crosslinking agent, and improve physical properties by increasing the degree of crosslinking. It relates to a foam composition applied with an inorganic chemical blowing agent with improved efficiency.
The present invention is a foam composition with improved foaming efficiency, 100 parts by weight of a base material, 2 to 6 parts by weight of an inorganic chemical foaming agent, 2 to 4 parts by weight of OBSH (4,4'-oxybis (benzene sufonyl hydrazide)), organic peroxide A foam composition comprising 1 to 3 parts by weight, 2 to 4 parts by weight of a metal oxide, and 0.5 to 1.5 parts by weight of an internal lubricant may be provided.

Description

Foam composition applied for inorganic chemical blowing agent with improved foaming efficiency}

The present invention relates to a foam composition using an inorganic chemical foaming agent with improved foaming efficiency, and more particularly, foaming that can increase the reaction rate by including citric acid, increase decomposition efficiency by including a co-crosslinking agent, and improve physical properties by increasing the degree of crosslinking. It relates to a foam composition applied with an inorganic chemical blowing agent with improved efficiency.

A foaming agent is a substance added to make a porous foam such as sponge or Styrofoam by combining with a polymer material. It is used to reduce raw materials due to the production of low-density products, improve electrical insulation, insulation, sound insulation, and shock absorption. , These foaming agents are classified into physical foaming agents and chemical foaming agents according to the gas release mechanism used to form the foam.

Physical blowing agents are a method of forming pores while undergoing physical change or volume change without chemical decomposition or structural change.

Chemical blowing agents are in the form of gas released by thermal decomposition or chemical reaction, and most of them are solid-state compounds that are vaporized in the form of evaporation or desorption without chemical change. It is divided into blowing agent and inorganic chemical blowing agent.

In general, as a blowing agent, ADCA (Azodicarbonamide) is mainly used as an organic chemical blowing agent, sodium bicarbonate is used as an inorganic chemical blowing agent, and OBSH (4,4'-Oxy Bisbenzene Sulfonyl Hydrazide), DPT (N,N'-Dinitroso-pentamethylenetetramine) is used as a chemical blowing agent.

However, ADCA (Azodicarbonamide) is widely used as a foaming agent due to its high foaming efficiency and low price. In addition, as REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) proposes to list ADCA as a regulatory permission substance, it is necessary to develop a blowing agent that can be used as a substitute for ADCA.

Recently, research on an eco-friendly foaming system excluding the ADCA system is in progress, and in the case of using a capsule foaming agent, there is a problem in that the hardness of the foam increases and the elasticity decreases while the capsule expands.

In addition, a method of using OBSH (4,4'-Oxy Bisbenzene Sulfonyl Hydrazide), which is mainly used in the manufacture of rubber-based foams, as a foaming agent has been proposed, but OBSH has a problem in that the raw material itself is expensive compared to ADCA.

In addition, a method of using a blowing agent based on an inorganic chemical blowing agent that does not generate any harmful gas has been proposed, but unlike organic chemical blowing agents, conventional inorganic chemical blowing agents have an endothermic reaction, so they decompose slowly in a wide range of temperatures. As the decomposition reaction occurs, the foaming efficiency is low, and accordingly, the inorganic chemical foaming agent has limitations even when an excessive amount of the inorganic chemical foaming agent is added to obtain the same foaming efficiency as the organic foaming agent.

In order to solve this problem, Korean Patent Registration No. 10-2191329 discloses a technology related to a foaming agent that effectively reduces ammonia gas generated during foaming of a foaming compound, but as is well known, ammonia gas is reduced to 120 ppm or less. Although it can be reduced, there is a problem that the generation of harmful ammonia gas cannot be completely prevented.

Republic of Korea Patent Registration No. 10-2191329 (2020.12.09.)

The present invention has been made to solve the above problems, and an object of the present invention is to provide a foam composition applied with an inorganic chemical blowing agent with improved foaming efficiency based on an inorganic chemical blowing agent that does not generate any harmful gas. .

Another object of the present invention is to provide a foam composition applied with an inorganic chemical blowing agent having improved foaming efficiency by increasing the decomposition reaction rate of the inorganic chemical blowing agent and improving the decomposition efficiency.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the present invention is a foam composition with improved foaming efficiency according to a preferred embodiment of the present invention, 100 parts by weight of a base substrate, 2 to 6 parts by weight of an inorganic chemical foaming agent, OBSH (4,4 ' -Oxy Bisbenzene Sulfonyl Hydrazide) 2 to 4 parts by weight, an organic peroxide 1 to 3 parts by weight, a metal oxide 2 to 4 parts by weight, and an internal lubricant 0.5 to 1.5 parts by weight may be provided.

Here, the base material is characterized in that it is selected from olefin resin, ethylene vinyl acetate resin, polyethylene resin, natural rubber, synthetic rubber, and mixtures thereof.

At this time, the inorganic chemical foaming agent is characterized in that selected from sodium bicarbonate, ammonium bicarbonate, sodium borohydride, and mixtures thereof.

In addition, the organic peroxides are dicumyl peroxide (DCP), 2,5-dimethyl-2,5-di (ter-butyl peroxyhexane, di-ter-butyl perterephthalate, ter-tert-butyl hydroperoxide and It is characterized in that it is selected from 1,3-bis (ter-butylperoxyisopropylene) benzene and mixtures thereof.

On the other hand, the foaming agent composition is characterized in that it further comprises 1 to 5 parts by weight of citric acid in order to improve foaming efficiency through a coupling reaction with the inorganic chemical foaming agent.

In addition, the foam composition is characterized in that it further comprises 0.3 to 0.7 parts by weight of a co-crosslinking agent in order to increase the decomposition efficiency of the initial inorganic chemical foaming agent and improve physical properties by increasing the degree of crosslinking.

In this case, the co-crosslinking agent is characterized in that it is selected from butylated hydroxy toluene (BHT), triallyl cyanurate (TAC), and mixtures thereof.

In addition, the metal oxide is zinc oxide, and the internal lubricant is characterized in that stearic acid.

As described above, the foam composition applied with an inorganic chemical foaming agent with improved foaming efficiency according to the present invention is based on an inorganic chemical foaming agent that does not generate harmful gases, so that harmful gases such as ammonia generated during foaming do not occur, which is harmful to the human body. It is harmless to the environment and has the advantage of being environmentally friendly.

In addition, the foam composition using an inorganic chemical foaming agent with improved foaming efficiency according to the present invention has the advantage of improving the low decomposition efficiency of the inorganic chemical foaming agent and improving physical properties by applying an additive.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to fully inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims.

Terms used in this specification are for describing the embodiments and are not intended to limit the present invention. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. As used herein, "comprises" and/or "comprising" does not exclude the presence or addition of one or more other elements other than the recited elements.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used in a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined.

Hereinafter, preferred embodiments of the present invention will be described in detail.

The foam composition with improved foaming efficiency according to the present invention includes a base material, an inorganic chemical foaming agent, OBSH, an organic peroxide, a metal oxide, and an internal lubricant, and further includes citric acid and a co-crosslinking agent.

According to a preferred embodiment, 100 parts by weight of a base material, 2 to 6 parts by weight of an inorganic chemical blowing agent, 2 to 4 parts by weight of OBSH (4,4'-Oxy Bisbenzene Sulfonyl Hydrazide), 1 to 3 parts by weight of an organic peroxide, 2 metal oxides to 4 parts by weight and 0.5 to 1.5 parts by weight of an internal lubricant, and further includes 1 to 5 parts by weight of citric acid and 0.3 to 0.7 parts by weight of a co-crosslinking agent.

First, the base material is selected from olefin resin, ethylene vinyl acetate resin, polyethylene resin, natural rubber, synthetic rubber, and mixtures thereof.

According to a preferred embodiment, the base substrate includes 100 parts by weight of an olefin resin alone.

Next, the inorganic chemical foaming agent is preferably selected from sodium bicarbonate, ammonium bicarbonate, sodium borohydride, and mixtures thereof.

According to a preferred embodiment, 2 to 6 parts by weight of the sodium bicarbonate is included. At this time, the sodium bicarbonate (sodium bicarbonate) is an inorganic chemical foaming agent, and does not generate harmful gases such as ammonia and formaldehyde, but has a problem of low foaming efficiency as decomposition slowly proceeds.

Accordingly, the present invention is a foam composition to which an inorganic chemical foaming agent is applied, which improves the foaming efficiency of the foaming agent and does not generate harmful gases.

The OBSH (4,4'-Oxy Bisbenzene Sulfonyl Hydrazide) is an organic chemical blowing agent that is not ADCA-based, and the present invention can improve the low foaming efficiency of the inorganic chemical blowing agent by including the OBSH. It is preferably included in 4 parts by weight.

At this time, the foaming agent composition with improved foaming efficiency according to the present invention includes the inorganic chemical foaming agent and the organic chemical foaming agent in a 1:1 ratio, and according to a preferred embodiment, the present invention is the inorganic chemical foaming agent, the sodium bicarbonate 3 parts by weight, including 3 parts by weight of the OBSH, the organic chemical blowing agent.

Next, the organic peroxide is dicumyl peroxide (DCP), 2,5-dimethyl-2,5-di (ter-butylperoxyhexane, di-ter-butyl perterephthalate, ter-tert-butyl hydroperoxide and 1,3-bis(ter-butylperoxyisopropylene)benzene and mixtures thereof.

In the present invention, the organic peroxide serves as a crosslinking agent and is preferably included in an amount of 1 to 3 parts by weight. If it is less than 1 part by weight, crosslinking is insufficient, and if it exceeds 3 parts by weight, the hardness increases rapidly, making it difficult to form a foam.

According to a preferred embodiment, the organic peroxide is included in 2 parts by weight of dicumyl peroxide (DCP).

Meanwhile, the foam composition according to the present invention further includes 1 to 5 parts by weight of citric acid in order to improve foaming efficiency through a coupling reaction with the inorganic chemical foaming agent.

The present invention can increase the decomposition reaction rate of the inorganic chemical blowing agent by including the citric acid, and specifically, when the sodium bicarbonate and the citric acid are used in combination, sodium bicarbonate As citric acid decomposes and a coupling reaction occurs, the initial decomposition temperature rises, but the decomposition temperature range narrows.

Here, the ratio of the sodium bicarbonate and the citric acid is 1: preferably 0.1 to 1.5, more preferably the sodium bicarbonate and the citric acid are included in a ratio of 1: 1, respectively, 3 parts by weight.

At this time, when the ratio of the sodium bicarbonate to the citric acid is less than 1: 0.1, the initial decomposition temperature is high, but the decomposition temperature range widens and the efficiency decreases, and when the ratio exceeds 1: 1.5, the initial decomposition reaction does not occur stably.

That is, the foam composition of the present invention preferably includes the inorganic chemical blowing agent: citric acid: OBSH in a ratio of 1: 1: 1, and the foaming efficiency of the inorganic chemical blowing agent is improved, as well as ammonia and It is eco-friendly because it does not generate harmful gases such as formaldehyde.

In addition, the blowing agent composition according to the present invention further includes 0.3 to 0.7 parts by weight of a co-crosslinking agent in order to increase the decomposition efficiency of the initial inorganic chemical blowing agent and improve physical properties by increasing the degree of crosslinking.

In the present invention, 'co-crosslinking agent' refers to a highly reactive monomer that increases the crosslinking density, and is used as an additive capable of obtaining a fast curing reaction in a free radical polymerization reaction, that is, as a kicker to increase the decomposition efficiency of an inorganic chemical blowing agent.

The co-cross-linking agent serves to increase the cross-linking degree of the foaming agent of the present invention and at the same time slow down the cross-linking rate. Specifically, the co-cross-linking agent is to improve the cross-linking degree while controlling the initial reaction rate, thereby increasing the decomposition efficiency of the initial inorganic chemical blowing agent. , improve the physical properties by improving the overall degree of crosslinking.

According to a preferred embodiment, the co-crosslinking agent is selected from butylated hydroxy toluene (BHT), triallyl cyanurate (TAC), and mixtures thereof, and contains 0.1 to 1.5 parts by weight.

At this time, the co-cross-linking agent preferably contains 0.3 to 0.7 parts by weight of butylated hydroxy toluene (BHT) alone, more preferably, the co-cross-linking agent is butylated hydroxy toluene (BHT) alone It is used and it is appropriate to include 0.5 parts by weight.

In addition, in the present invention, a metal oxide and an internal lubricant may be used as additives to form a foam.

Here, the metal oxide is appropriately selected from zinc oxide, magnesium oxide, and mixtures thereof, and is preferably included in an amount of 2 to 5 parts by weight based on 100 parts by weight of the base substrate.

According to a preferred embodiment, the metal oxide is included in 3 parts by weight of the zinc oxide alone.

Next, the internal lubricant is suitably selected from stearic acid, common internal lubricants, and mixtures thereof, and the internal lubricant reduces mutual frictional force between the foaming agent composition and the processing machine to facilitate processing, It is preferably included in 0.5 to 2 parts by weight based on 100 parts by weight.

According to a preferred embodiment, the internal lubricant contains 1 part by weight of stearic acid alone.

More preferably, the present invention includes 3 parts by weight of the metal oxide zinc oxide (ZnO) as an additive included in the foaming agent composition and 1 part by weight of stearic acid as the internal lubricant, thereby facilitating processing and molding of the foam. can do.

In addition, the filler is calcium carbonate, magnesium carbonate, titanium oxide, silica, etc., and the accelerator is mercaptobenzothiazole (MBT), dibenzothiazole disulfide (MBTS), dipentamethylene thiuram tetrasulfide (DPTT) The processing oil may be paraffin oil, naphthene oil, castor oil, canola oil or soybean oil, but is not limited thereto, and various types of foam additives already known in response to the usage or use environment of the foam composition are used. can be applied for the purpose.

On the other hand, the foam composition according to the present invention is put into a closed mixer and kneaded at 95 to 120°C for 10 minutes, and the foam molding conditions are 150 to 200°C and 100 to 150 kgf/cm ² for 5 to 20 minutes to prepare a foam. can do.

At this time, the foam composition is kneaded and softened at a temperature of 95 to 120 ° C., and when the temperature is out of the above range during softening, non-uniform crosslinking may occur.

In addition, when molding the foam, it is heated at a temperature of 150 to 200 ° C. In this temperature range, the crosslinking agent is decomposed and the crosslinking reaction proceeds, so that the viscosity and elasticity can be adjusted within a certain range, and the foaming of the inorganic chemical foaming agent according to the present invention Performance and physical properties are improved.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments, comparative examples, and experimental examples of the present invention. However, the following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited to the following examples. Contents not described herein can be technically inferred by those skilled in the art, so description thereof will be omitted.

Example 1

100.0 g of olefin resin, 3.0 g of sodium bicarbonate as an inorganic chemical blowing agent, 3.0 g of citric acid, 2.0 g of DCP as an organic peroxide, 0.5 g of BHT as a co-crosslinking agent, 3.0 g of OBSH, 3.0 g of zinc oxide as a metal oxide and internal lubricant 1.0 g of low stearic acid was added to a closed mixer and kneaded at 100° C. for 10 minutes to prepare a foam sheet, and the foam sheet was molded at 170° C. for 7 minutes under 120 kgf/cm ² conditions to prepare a foam body.

Example 2

It was prepared in the same manner as in Example 1, but the content was changed to 0.3 g of BHT and 2.0 g of OBSH as a co-crosslinking agent, and then put into a closed mixer and kneaded at 100 ° C. for 10 minutes to prepare a foam sheet. A foam was prepared by molding for 7 minutes under a cm ² condition.

Comparative Example 1

A co-crosslinking agent was not added, and the content was changed to 2.0 g of sodium bicarbonate and 2.5 g of OBSH as an inorganic chemical foaming agent, and was prepared in the same manner as in Example 1.

Comparative Example 2

It was prepared in the same manner as in Example 1, without adding OBSH, citric acid, and a co-crosslinking agent, and changing the content of 5.0 g of sodium bicarbonate with an inorganic chemical foaming agent.

Comparative Example 3

It was prepared in the same manner as in Example 1 by mixing the components shown in Table 1 and putting them into a closed mixer.

Comparative Example 4

It was prepared in the same manner as in Example 1 by mixing the components shown in Table 1 and putting them into a closed mixer.

ingredient Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 olefin resin 100 inorganic chemical blowing agent 3.0 2.0 2.5 5.0 - - OBSH 3.0 2.0 2.5 - - - ADCA - - - - 5.0 3.0 organic peroxide 2.0 2.0 2.0 2.0 2.0 2.0 citric acid 3.0 3.0 3.0 - - - dating 0.5 0.3 - - - - zinc oxide 3 stearic acid One Molding conditions 170℃×8min [10T mold]

Test Example 1 - Measurement of physical properties

Experimental Example 1 is for measuring physical properties, and the physical properties of the foam sheets prepared according to Examples 1 to 2 and Comparative Examples 1 to 4 were measured, and the results are shown in Table 2 below.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Specific Gravity (Sp.Gr.) 0.23 0.23 0.23 0.30 0.14 0.23 Hardness (Asker C) 45 45 45 50 40 45 Permanent compression set (C set, %) 50 51 55 65 60 50 Resilience (%) 60 60 60 60 60 60

As shown in Table 2, Example 1 included the inorganic chemical blowing agent, the OBSH, and the citric acid in a ratio of 1: 1: 1, and Example 1 was more permanent than Example 2 in which the ratio was different. It can be seen that the durability is improved due to the low compression set, and the physical properties are the best.

In addition, it can be seen that the compression set of Example 1 is greatly improved compared to Comparative Example 1 not including the co-crosslinking agent and Comparative Example 2 not including the citric acid, OBSH, and the co-crosslinking agent, and ADCA, a conventional blowing agent. It can be seen that the overall physical properties are improved compared to Comparative Examples 3 and 4 using.

Test Example 2 - Measurement of Ammonia Generation

Experimental Example 2 is for measuring the amount of ammonia generation. After keeping the foam at room temperature for 1 hour, cutting it into 10cm × 10cm, putting it in a 5L Tedlar bag, sealing it, and then filling it with N ₂ gas using a pump. After leaving the 5L tedler bag for 1 hour, the ammonia release concentration (ppm) in the 5L tedler bag was measured using an ammonia detector tube, and the results are shown in Table 3 below.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 50℃×1hr 0 0 0 0 70 60 70℃×1hr 0 0 0 0 120 100

As shown in Table 3, Examples 1 and 2 according to the present invention are compared to Comparative Examples 1 to 4, specifically, compared to Comparative Examples 3 and 4 prepared using the ADCA blowing agent that has been used in the prior art. In Example 1 and Example 2, as the ammonia concentration was 0 ppm and no ammonia was detected, it can be confirmed that the amount of ammonia generated by the blowing agent according to the present invention was significantly improved.

Therefore, since the present invention does not generate ammonia gas, which is a harmful gas generated during foaming, it is possible to prevent ammonia gas from being exposed to ammonia gas during work and remaining in the material to affect the human body and the environment.

Although the embodiments of the present invention have been described as described above, those skilled in the art can understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. There will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (8)

In the foam composition with improved foaming efficiency,
100 parts by weight of base material, 2 to 6 parts by weight of inorganic chemical foaming agent, 2 to 4 parts by weight of OBSH (4,4'-Oxy Bisbenzene Sulfonyl Hydrazide), 1 to 3 parts by weight of organic peroxide, 2 to 4 parts by weight of metal oxide and internal Including 0.5 to 1.5 parts by weight of a lubricant,
The foam composition,
In order to improve the foaming efficiency by the coupling reaction with the inorganic chemical foaming agent, 1 to 5 parts by weight of citric acid is further included,
Contains the inorganic chemical foaming agent, citric acid, and OBSH in a ratio of 1: 1: 1 so as not to generate harmful gases,
A foam composition characterized in that it further includes 0.3 to 0.7 parts by weight of butylated hydroxy toluene (BHT) as a co-crosslinking agent to increase the decomposition efficiency of the initial inorganic chemical foaming agent and improve physical properties by increasing the degree of crosslinking. According to claim 1,
The base material is a foam composition, characterized in that selected from olefin resin, ethylene vinyl acetate resin, polyethylene resin, natural rubber, synthetic rubber and mixtures thereof According to claim 1,
The inorganic chemical foaming agent is a foam composition, characterized in that selected from sodium bicarbonate, ammonium hydrogen carbonate, sodium borohydride and mixtures thereof. According to claim 1,
The organic peroxides include dicumyl peroxide (DCP), 2,5-dimethyl-2,5-di(ter-butylperoxyhexane, di-ter-butylperterephthalate, ter-tert-butylhydroperoxide and 1, A foam composition characterized in that it is selected from 3-bis(ter-butylperoxyisopropylene)benzene and mixtures thereof. delete delete delete According to claim 1,
The metal oxide is zinc oxide,
The foam composition according to claim 1, wherein the internal lubricant is stearic acid.