TWI601807B - Auxiliary composition, foam and method for fabricating thereof - Google Patents

Description

Auxiliary composition, foam and preparation method thereof

The present invention relates to an auxiliary composition, and more particularly to an auxiliary composition for balancing a foaming rate and a bridging rate, and a foam for use thereof and a method for preparing the same.

The shoes have the function of protecting the feet. To make the user feel comfortable and reduce the burden, lightweight has become an important appeal for shoes. At the same time, other functions such as buffering, sound absorbing, shock absorbing, and heat preservation are also very important for shoe materials. Therefore, foaming of polyolefin plastics such as ethylene-vinyl acetate copolymer (EVA) is used as the substrate. The body has been widely used in the manufacture of shoes. That is to say, the ethylene-vinyl acetate copolymer can achieve the aforementioned functions by foaming, and the foaming can also reduce the specific gravity to achieve the purpose of reducing cost and light weight.

However, the foaming process of the ethylene-vinyl acetate copolymer takes time. If the daily output is to be increased and the energy consumption of the product is lowered, an auxiliary agent may be appropriately added to shorten the time required for foaming. At present, urea is mostly used as an auxiliary agent to reduce the foaming activation energy of a foaming agent (such as azomethicin), so that the foaming agent accelerates decomposition, and the urea and the foaming agent are accelerated when decomposed. An exothermic reaction occurs, which in turn causes the bridging agent to gain energy and accelerate decomposition. However, this type of reaction method is to make the foaming rate higher than the bridging rate, so although it has the effect of accelerating the foaming reaction of the ethylene-vinyl acetate copolymer, since the foaming rate is too fast, it is easy to make the obtained hair. The surface of the bubble produces spots which cause uneven color appearance and greatly reduce product quality.

Furthermore, the products currently used on the market for accelerating the foaming rate are mostly in the form of powders, but these powdery products have the following three disadvantages: (1) are difficult to control in terms of ingredients, and (2) are easy to be environmentally friendly, The human body causes injury; and (3) the foaming rate is relatively fast, which makes the appearance of the product surface poor.

In view of this, how to develop an additive that can reduce the time required for the foaming reaction in use, and that can also avoid the appearance of poor foaming rate and bridging rate, is actually desired by the industry. The goal.

One embodiment of an aspect of the present invention provides an auxiliary composition comprising 30% by weight to 50% by weight of a carrier resin, 4% by weight to 85% by weight of urea, and 15% by weight to 25% by weight. Zinc oxide powder, 3 to 8 weight percent bridging aid, and 20 to 40 weight percent additive.

The adjuvant composition according to the above embodiment, wherein the carrier resin may be an ethylene vinyl acetate resin, and the content of vinyl acetate (Vinyl Acetate, VA) may be greater than or equal to 18 weight percent.

The adjuvant composition according to the foregoing embodiment, wherein the bridging aid may be Triallyl cyanurate (TAC), triallyl isocyanurate (TAIC) or a mixture thereof. .

The adjuvant composition according to the foregoing embodiment, wherein the aforementioned additive may comprise talc, and the content of the talc in the total amount of the adjuvant composition is from 20% by weight to 35% by weight.

The adjuvant composition according to the preceding embodiment, wherein the aforementioned additive may comprise zinc stearate, and the zinc stearate is present in an amount of from 1% by weight to 5% by weight based on the total amount of the auxiliary composition.

The adjuvant composition according to the preceding embodiment, wherein the aforementioned adjuvant composition may be in the form of pellets.

Another embodiment of the present invention provides a foam, and the foam may be prepared from a foamed composite material, wherein the foam composite comprises at least a substrate, a bridging agent, and a foaming composite. A blowing agent and the aforementioned auxiliary composition.

The foam according to the above embodiment, wherein the auxiliary agent composition is used in an amount of from 0.1 part by weight to 1.5 parts by weight per 100 parts by weight of the substrate.

Thereby, the auxiliary composition of the invention simultaneously contains urea, bridging aid and zinc oxide powder, and can further balance the foaming rate and the bridging rate while accelerating the foaming. In this way, the gas generated during foaming can be stably wrapped in the network structure of the bridge to avoid the occurrence of spots on the surface of the prepared foam.

One embodiment of another aspect of the present invention provides a preparation method for preparing the aforementioned foam. First, the aforementioned foamed composite material is provided. Next, a vulcanization molding step is performed to foam the foamed composite material to obtain a foam.

According to the production method of the foregoing embodiment, the vulcanization molding time of the aforementioned vulcanization molding step may be from 4.5 minutes to 5 minutes.

The Summary of the Invention is intended to provide a simplified summary of the present disclosure in order to provide a basic understanding of the disclosure. This Summary is not an extensive overview of the disclosure, and is not intended to identify the essential/critical elements of the embodiments of the invention or the scope of the invention.

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S102‧‧‧Steps

The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood. 1 is a flow chart showing a preparation method of an embodiment of the present invention.

The various embodiments of the invention are discussed in more detail below. However, this embodiment can be applied to various inventive concepts and can be embodied in various specific ranges. The specific embodiments are for illustrative purposes only and are not limited by the scope of the disclosure.

The present invention is directed to providing an adjuvant composition comprising a carrier resin, urea, zinc oxide powder, bridging aids and additives. It should be noted that the auxiliary composition of the present invention contains urea, bridging aid and zinc oxide powder at the same time. Foaming is accelerated in subsequent processes and the foaming rate and bridging rate are further balanced. In this way, the gas generated during foaming can be stably wrapped in the network structure of the bridge to avoid the occurrence of spots on the surface of the prepared foam.

First, the carrier resin contained in the auxiliary composition of the present invention is used to carry the above-mentioned components, so that the above components can be uniformly dispersed in the carrier resin, which is advantageous for subsequent granulation to make the auxiliary composition granules. shape. Thereby, the granule-like auxiliary composition is easier to control than the conventional powdery product in terms of the material and the ingredients, and has no dust problem, and will not cause harm to the environment or the human body. In addition, since the material itself has been pre-dispersed to contribute to uniform foaming, the overall appearance of the product foam can be further improved.

The carrier resin may be, for example, polyethylene (PE), polypropylene (PP), and copolymers such as ethylene-vinyl acetate, poly(oxyethylene), POE, methyl methacrylate. An olefin polymer such as Methyl methacrylate (MMA), which may be selected from the same or different materials as the substrate of the subsequent foam, and the present invention is not intended to be limited thereto. Further, the carrier resin of the present invention may specifically be an ethylene-vinyl acetate copolymer, and the processing temperature is not too high, so the content of vinyl acetate in the ethylene-vinyl acetate copolymer selected in the present invention is greater than Or equal to 18 weight percent.

Next, it must be understood that the foamed composite material generally used to obtain the foam generally comprises a substrate, a bridging agent, a foaming agent, and various additives such as fillers, colorants, and slip agents. The foaming agent acts to produce a foaming reaction at a specific temperature, that is, the blowing agent decomposes at a specific temperature. A gas is generated to cause the substrate to have a pore structure and cause expansion of the volume of the plastic substrate. However, when a blowing agent H (such as N, N'-dinitrosopentamethylenetetramine) or a blowing agent AC (such as azomethicin) is used as the main foaming agent, its decomposition The temperature is too high, which is not conducive to the processing of normal foam products. Therefore, the adjuvant composition of the present invention contains both urea and zinc oxide powder, which can be used to lower the decomposition temperature of the foaming agent, thereby accelerating the decomposition of the foaming agent. In other words, the foaming rate in the subsequent foaming process can be adjusted by adding urea and zinc oxide powder, and by adjusting the ratio of urea and zinc oxide powder in the auxiliary composition, The subsequent foaming process has different foaming effects. Therefore, in the present invention, the content of urea in the total amount of the auxiliary composition may specifically be 4 to 8 weight percent, and the content of the zinc oxide powder in the total weight of the auxiliary composition may specifically be 15 weight percent to 25 weight percent.

According to the above, the bridging agent in the foaming composite material acts to crosslink between different chains of the chain polymer of the substrate, and becomes a network structure, which can increase the strength and elasticity of the plastic substrate, thereby improving The mechanical properties of the resulting foam also play an important role in the foaming process. By increasing the strength and elasticity of the foamed plastic substrate, the pore structure of the substrate can capture the gas generated by the foaming agent. The gas is not easily dissipated, and the pore structure is maintained without the reaction of defoaming due to collapse. Accordingly, the adjuvant composition of the present invention further comprises a bridging aid for participating in the bridging reaction to enhance the bridging density and reducing the chance of spotting on the surface of the subsequently produced foam. Specifically, the amount of the bridging aid in the total weight of the auxiliary composition may be from 3 to 8 weight percent. In addition, the bridging aid used herein may be triallyl cyanurate, triallyl isocyanurate or a mixture thereof, and the present invention does not intend to Limited.

The aforementioned adjuvant composition may specifically further comprise from 20% by weight to 40% by weight of the additive. In particular, the additive may contain talc, which may be used to enhance the dispersibility of the material, and specifically comprises from 20% by weight to 35% by weight based on the total amount of the auxiliary composition.

In addition, the additive may further comprise zinc stearate. In addition to being used to enhance the dispersibility of the material, the addition of zinc stearate further reduces the heat accumulated during processing. That is to say, an appropriate amount of zinc stearate can promote the smooth progress of bridging and foaming, but its excessive amount may cause the bridging speed to be much lower than the decomposition speed of the foaming agent due to excessive acidity, so it accounts for the additive combination. The content of the total amount of the substance is specifically from 1% by weight to 5% by weight.

The components of the auxiliary agent composition provided by the present invention have been roughly described as above. Although the following description of the preparation method of the auxiliary agent composition is as follows, the preparation method can be combined with, but not limited to, a single screw extrusion. Take the opportunity to proceed. First, each of the above components is uniformly mixed in the above-mentioned single-screw extruder and discharged, and granulated to obtain a particulate material. Next, the obtained particulate material was first cooled by air-cooling, and then dispersed by a vibrating sieve to perform second cooling. Finally, the cooled pellets can be placed in a mixing tank. Specifically, the operating temperature setting of the foregoing process may be from 85 ° C to 90 ° C from the inlet to the discharge port, but the invention is not intended to be limited thereto.

At this time, the present invention further provides a foam using the aforementioned auxiliary composition and a method for producing the same. In detail, the foaming system is prepared from a foamed composite material, and the foamed composite material comprises at least a substrate and a bridge. The agent, the foaming agent and the aforementioned auxiliary agent composition, and the respective components of the auxiliary agent composition and the possible proportions thereof have been described in detail as before, and will not be described herein.

Please refer to FIG. 1 . FIG. 1 is a flow chart showing a method for preparing a foam according to an embodiment of the present invention, and includes steps S100 and S102 . First, as shown in step S100, the foamed composite material described above is provided as a mixed base material, a bridging agent, a foaming agent, and an auxiliary composition. It should be noted, however, that the foamed composite material described above may further contain other additives, for example, stearic acid which is useful for stripping or additional additives such as zinc oxide powder, zinc stearate, talc, and the like.

Specifically, the foregoing substrate may be polyethylene, polypropylene, and an olefin polymer such as ethylene-vinyl acetate copolymer, polyoxyethylene, methyl methacrylate, etc., and the foaming agent may be, for example, sodium bicarbonate and sodium carbonate. An inorganic blowing agent such as ammonium hydrogencarbonate, ammonium carbonate or ammonium nitrite, or such as N,N'-dinitrosopentamethylenetetramine and N,N'-dinitroso-p-benzoquinone A nitroso compound such as an amine, an azo compound such as azodimethylamine or azobisisobutyronitrile, an oxime compound such as benzenesulfonate or 4,4'-oxybis(phenylsulfonate), or a stack of An organic foaming agent such as calcium nitride or an azide such as 4,4'-diphenyldisulfonium azide, which may be used singly or in combination of two or more, and the bridging agent may be an odorless bridging agent, for example, , 4-t-butylperoxy isopropyl benzene (BIBP), but the invention is not intended to be limited to any of the foregoing examples.

Next, as shown in step S102, a vulcanization molding step is performed to foam the foamed composite material to obtain a foam. When performing step S102, a sulfur analyzer can be used to determine the sulfide curve at the general molding temperature. Line, and then judge the degree of vulcanization from MH, T10 and T90 in the vulcanization curve, where MH is the highest point on the vulcanization curve, which represents the highest torque and can be seen from the fully vulcanized shear mode of the foamed composite. Quantity or stiffness, T10 is basically the starting point of the bridging reaction, that is, the time required to reach 10% of MH can reflect the scorch time of the foamed composite, and T90 is required to reach 90% of MH The time of the vulcanization of the foamed composite can be reflected by the time. At this time, it can be judged by T90 whether the aforementioned auxiliary agent composition can effectively accelerate the progress of the overall foaming reaction, and the shrinkage rate of the obtained foam can be further tested according to the method specified in the ASTM D1917 standard, and the current shrinkage rate. Below 2% is the current industry standard. Further, the foaming effect can be further judged by the appearance of the foam described above.

The auxiliaries of the present invention and their achievable effects will be further described in detail below with reference to specific examples and comparative examples, and the auxiliaries compositions of Examples 1 to 3 and Comparative Examples 1 to 4 will be further exemplified. The composition, the vulcanization performance, the shrinkage ratio, and the appearance of the obtained foam were separately shown in Tables 1 and 2. Wherein, the appearance of the foam does not have a spotted flower or has only a few spots and can be modified by titanium dioxide without affecting the appearance of the subsequent product, and is evaluated as "○", whereas when the appearance of the foam has a large amount of spotted If it is not possible to overcome the appearance of the subsequent product with titanium dioxide, it will be rated as "X".

It is to be noted that the components of the foamed composite materials of Examples 1 to 3 and Comparative Examples 1 to 4 are in addition to the auxiliary composition based on 100 parts by weight of the ethylene-vinyl acetate copolymer (as a substrate). Further comprising 10 parts by weight of talc, 1.5 parts by weight of zinc oxide powder, 0.5 parts by weight of zinc stearate, 1 part by weight of stearic acid, 1.9 parts by weight of foaming agent and 0.5 weight a bridging agent, and the above 100 parts by weight of the ethylene-vinyl acetate copolymer is composed of 85 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 21% by weight (VA is 21% by weight of EVA) and 15 parts by weight. The mixture was composed of an ethylene-vinyl acetate copolymer (VA of 33% by weight of EVA) having a vinyl acetate content of 33% by weight. Further, the auxiliary composition of the foamed composite materials of Examples 1 to 3 and Comparative Examples 1 to 4 was fixed to 1 part by weight with respect to 100 parts by weight of the ethylene-vinyl acetate copolymer, to further The relevance of the ingredients in the adjuvant composition to the desired effect is discussed.

Referring to Table 1 and Table 2 together, with Example 1, Comparative Example 1 and Comparative Example 2, in Comparative Example 1 and Comparative Example 2, T90 is slower, that is, the required processing time is longer and the accelerated reaction cannot be achieved. The effect. When the zinc oxide powder accounts for 40% by weight of the total weight of the auxiliary composition, the shrinkage has exceeded the standard of 2%, and the appearance of the obtained foam has a noticeable spot.

Next, in the case of Example 1, Example 2 and Comparative Example 3, when the content of urea in the auxiliary composition is 5 weight%, T90 is short, and it is sufficient that the auxiliary composition of Example 1 can accelerate the reaction. And the shrinkage rate is within the standard, and the appearance of the obtained foam is also free of spots. Furthermore, as shown in Example 2, when the content of urea in the auxiliary composition is increased from 5 weight percent to 7.5 weight percent, T90 is further shortened, and the shrinkage ratio at this time is still within the standard of 2%, and is prepared. Although the appearance of the obtained foam is slightly speckled, it can still be modified by titanium dioxide without affecting the appearance of the subsequent product, and can still be said to conform to the standard product. However, when the content of urea in the auxiliary composition is further increased to 10% by weight, the shrinkage rate is shortened although T90 is also shortened. It has exceeded the standard of 2%, and the foaming rate is too fast, so that the surface of the obtained foam has obvious speckle.

Further, in the case of Example 1, Example 3 and Comparative Example 4, when the content of the bridging aid in the auxiliary composition is increased from 5 weight percent to 7.5 weight percent, the T90 can be shortened and the shrinkage rate is still 2%. In the standard, and the appearance of the obtained foam is slightly speckled, it can be modified by titanium dioxide without affecting the appearance of the subsequent product, and can still be said to conform to the standard product. However, when the content of the bridging aid in the auxiliary composition is further increased to 10% by weight, although the T90 can be made shorter, the shrinkage rate has exceeded the standard of 2%, and the foaming rate is too fast. The surface of the resulting foam produced a noticeable spot.

Further, referring to Table 3, the present invention further adjusts the content of the auxiliary composition in the foamed composite material to observe its effect on the foaming effect, wherein the foamed composite material of Example 4 is not added with the auxiliary composition. Further, in addition to the auxiliary composition, the foam composite material of Examples 4 to 6 further contains 10 parts by weight of talc based on 100 parts by weight of the ethylene-vinyl acetate copolymer (as a substrate). 1.5 parts by weight of zinc oxide powder, 0.5 parts by weight of zinc stearate, 1 part by weight of stearic acid, 1.9 parts by weight of a foaming agent and 0.5 parts by weight of a bridging agent, and the aforementioned 100 parts by weight of ethylene-acetic acid The vinyl ester copolymer was composed of 85 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 21% by weight and 15 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 33% by weight. Further, Examples 5 to 6 employed the adjuvant composition of Example 1.

It can be seen from Example 4 that when the auxiliary composition is not added, although a foam having an appearance conforming to the standard can be obtained, the T90 is remarkably slow, which is disadvantageous for subsequent applications. Further, from the viewpoints of Example 5 and Example 6, when the amount of the auxiliary composition used was 1 part by weight based on 100 parts by weight of the substrate, it was possible to obtain a foam having an appearance conforming to the standard. And when the amount of the auxiliary composition is increased to 1.5 parts by weight, not only the T90 is shortened, but also the overall vulcanization molding time can be shortened by 60 seconds to 90 seconds (generally, for the additive composition without added and having a thickness of 10) For the millimeter test piece, the vulcanization molding time is about 360 seconds, and the vulcanization molding time can be adjusted to 270 seconds to 300 seconds after the addition of the auxiliary composition, and the obtained foam appearance can only be obtained. Titanium dioxide overcomes a little spotted. Therefore, when the auxiliary composition of the present invention is used in an odorless formula, the amount of the odorless bridging agent can be effectively reduced, the condition of the mold mucus caused by the odorless bridging agent residue phenomenon is avoided, and the appearance defect rate of the foam is lowered. produce.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention can be modified and modified without departing from the spirit and scope of the present invention. The scope is subject to the definition of the scope of the patent application attached.

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Claims (10)

An auxiliary composition comprising: 30% by weight to 50% by weight of a carrier resin; 4% by weight to 85% by weight of urea; 15% by weight to 25% by weight of zinc oxide powder; and 3% by weight to 85% by weight of a bridge Auxiliary; and 20% by weight to 40% by weight of the additive. The auxiliaries composition according to claim 1, wherein the carrier resin is an ethylene vinyl acetate resin, and the content of vinyl acetate is 18% by weight or more. The adjuvant composition of claim 1, wherein the bridging aid is triallyl cyanurate, triallyl isocyanurate or a mixture thereof. The auxiliaries composition of claim 1, wherein the additive comprises talc, and the talc comprises from 20% by weight to 35% by weight based on the total amount of the auxiliaries. The auxiliaries composition of claim 1, wherein the additive comprises zinc stearate, and the zinc stearate comprises from 1% by weight to 5% by weight of the total amount of the auxiliaries. The auxiliaries composition of claim 1, wherein the auxiliaries are in the form of granules. A foam obtained by preparing a foamed composite material, wherein the foamed composite material comprises at least a substrate, a bridging agent, a foaming agent, and in items 1 to 6 of the patent application scope An adjuvant composition as claimed in any of the preceding claims. The foam according to claim 7, wherein the auxiliary composition is used in an amount of from 0.1 part by weight to 1.5 parts by weight per 100 parts by weight of the substrate. A preparation method for preparing the foam according to claim 7, comprising: providing the foamed composite material; and performing a vulcanization molding step of foaming the foamed composite material to obtain the foam Foam. The preparation method according to claim 9, wherein the vulcanization molding step has a vulcanization molding time of from 4.5 minutes to 5 minutes.