novel tpvs exhibit excellent adhesion to textile fibers during melt processing. - characteristics of polyester
Engineering thermofix and thermoplastic rubber are used in combination with reinforced materials such as textile ropes and fabrics for engineering composites and mechanical rubber products.
Some examples of these applications are industrial hoses, light conveyor belts and fabric reinforcement plates.
The degree of adhesion between the rubber and the reinforcement plays an important role in the final strength and overall performance of the final composite structure.
In general, the elastic body needs to use a yarn treatment or bonding system to facilitate adhesion to the enhanced substrate.
The treated yarn is chemically adhered to the hot-solid rubber material during the vulcanization step.
These treated yarns are chemically bonded by the active end-base of the adhesive polymer.
These end bases usually have the functions of oh, carboxyl and amine.
The main treatment method used for the bonding of yarn with heat shrink is based on phenol, formaldehyde and latex (RFL)
, Orisocyanate systemref. 1).
The application of these liquid yarntreatments occurs during dip operation.
Then, during the drying and curing process of the oven fired directly or indirectly, the adhesion of the oil-immersed treatment to the surface of the yarn occurs.
The resulting adhesion between the fiber and the dip, as well as the ipto of the thermosolid rubber, is a powerful function of the curing time and temperature after the dip operation.
If the combination of time and temperature is not enough, then the degree of adhesion between the treatment and the yarn will not be ideal.
If the soaked Yaris is overexposed during curing and drying, then the adhesion between the treatment and the fibers may be satisfactory, but the adhesion between the treatment and the hot-solid rubber is affected
In a flexible composite structure, the adhesion of the thermoplastic to the fabric reinforcement is achieved by using the reactivity and/or hot melt adhesive that is usually applied after melting treatment.
Melt Processing is a general term for describing the thermoplastic forming process.
These processes include injection molding, extrusion, blow molding and thermoforming.
Compared to similar hot-solid rubber operations, the cycle time associated with these processes is very short due to the vulcanization steps.
The lack of available time at high temperatures associated with thermoplastic processing hinders the widespread use of dip treatment in the bonding of thermoplastic rubber to yarn.
Therefore, it is common to use some structural adhesive to adhere the fiber to the molded thermoplastic surface.
For example, when manufacturing a high-pressure thermoplastic hose, the fibers are bonded to the thermoplastic pipe and the covering material using a damp polyurethane adhesive.
These adhesives usually take 72 hours to achieve full curing.
In addition, these adhesive systems tend to increase the weight and stiffness of the finished structure.
The reduction in elasticity is due to the tendency of the adhesive to enter the woven reinforcement.
Once the adhesive dipping fiber is cured, the stiffness of the hose assembly is increased and the flexibility is reduced.
The current work covers the development of a new type of tpv, which is formulated to demonstrate excellent adhesion to polyamide and polyester-enhanced materials during melting processing.
These new TPV formulations show a peel strength greater than 50 N/2 cm (15 pli)
Polyester and nylon fibers when the cross is extruded.
This excellent level of bonding with textiles combines the lightweight and flexible properties of the TPVs, helping to improve the performance of engineering composite structures.
Experimental evaluation of the existing adhesive technology this technical effort initially focused on the development of a method to adhere tpv to the fiber reinforcement to achieve greater penetration into the application and structure of flexible composites.
The biggest obstacle widely accepted by olefinic TPVs in fiber reinforced structures is their poor adhesion properties.
The Olefinic TPVs produced by the dynamic vulcanization process are usually composed of cross-linked ethylene-propylene rubber particles in the continuous phase of polypropylene.
Oron of Oron
The polarity of the TPV makes it difficult to glue to different surface chemicals using traditional adhesive systems.
Polypropylene, for example, 30-with low surface energy-33 dyne/cm.
The low surface energy and polarity of olefin, the lack of functional resin make it difficult to moisten satisfactorily using epoxy, polyurethane and acrylic structural adhesives.
These types of adhesives exhibit a higher surface energy than polypropylene or polyethylene and, therefore, they tend to accumulate on the surface of TPV, showing poor moisture rather than forming a continuous adhesive film.
By using surface treatment and primers, the low surface energy of these olefinic TPVs can be improved.
Mechanical pretreatment such as plasma discharge, flame treatment and chemical/solvent treatment are used throughout the market to improve the adhesion to Thermoplastic olefin (refs. 2-4).
The overall impact of these pre-treatments on the adhesive properties of TPVs varies depending on many process and composition factors.
The content and composition of rubber in TPV formula have a significant impact on adhesion.
The effect of mechanical pretreatment is related to the degree of oxidation of the attached surface.
The oxidation of the polymer results in an increase in the surface area, making it easier to attach and coat.
The ability of the oxidized surface is also strongly dependent on the composition of the TPV.
Tpv based on natural rubber has been shown to accept halogen treatment (ref. 5).
Oil and fillers commonly present in the cross-linked rubber phase of Tpvp will prevent oxidation and surface modification.
Primer such as olefin chloride (CPO)
Has been successfully used as a "tie"
"Coating" to improve the pain and adhesion of the surface of the thermoplastic olefin.
These primers, which are usually aggregated in the solvent, increase the surface area of TPV through its polar function.
It is also important that these materials reduce the crystalline degree of the TPV surface, thus improving the bonding performance using traditional coating and structural bonding systems.
Table 1 shows the effect of pretreatment on the surface energy of the folefinic TPV material.
Both untreated TPVs exhibit very low surface energy.
The Corona and flame pre-treatment is carried out at a line speed of 17 feet per minute on the stock of the flat material.
After both types of treatment, the surface features of TPV were significantly improved.
As the hardness of the material increases, the response of TPV to surface pretreatment increases.
This improvement can be related to the level of polypropylene in TPV.
The chloride polypropylene primer assessed in this study did not show the same improvement in surface energy.
Based on these results, corona will be the preferred surface pretreatment for use in conjunction with conventional adhesive systems.
The universal adhesive system used in industry to bond elastic material yarns for high pressure thermoplastic hoses is a single-component polyurethane adhesive.
For more than 20 years, these wet-cured polyurethane have been used to glue copolyetherester, polyamide and TPU materials into textile enhancements.
These liquid systems are available in solvent and 100% solid form.
Typically, it takes 72 hours for the adhesive system to fully solidify with moisture to develop the final adhesive performance.
Once cross-linked, these polyurethane systems exhibit excellent fatigue resistance and temperature resistance.
Table 2 shows the adhesion results of 64 shore a olefinic TPVbonded combined with E-
Coated steel using surface pretreatment and wet curing polyurethane adhesive.
The peel strength results show that the peel performance of the chloro-olefin primer is better than that of the corona and flame surface treatment.
The failure mode of all samples is adhered to the surface of TPV pretreatment.
These peel results are combined with the data in Table 1, indicating that the adhesion between polyurethane and TPV is not only dependent on the degree of moisture on the surface.
The surface morphology of the Tpvo may be affected, which helps to improve the peel strength of the adhesive using a chlorine-substituted olefin primer in combination with a traditional adhesive system.
Although the primer-treated TPV provides better overall peel strength, the adhesion level is still too low in flexible composite applications.
The entire flexible composite industry is looking for a level of adhesion greater than or equal to 42 N/2 cm.
The adhesion results show that in order to enhance the fibers using a structural bonding system connecting the TPV, the olefinic TPV surface must be pre-treated with a primer.
Unfortunately, many of these primers are solvent-based.
Although these pre-treatments improve the overall bonding strength, the resulting failure mode is usually the adhesion to the TPV surface.
Another drawback of these types of adhesive systems is that the assembly time of moisture-cured polyurethane is also different as environmental conditions change.
Based on the adverse results obtained using traditional bonding techniques, a textile bonded TPV material is developed that will adhere directly to the surface of the fiber during melting without the use of pretreatment, dipping treatment of adhesive or yarn.
During the melting process, standard olefinic TPVs usually have poor adhesion to polyester and polyamide fibers.
The typical range of textile fiber adhesive peel strength is 1. 0 to 3. 0 N/2cm.
This low level bonding is due to the lack of intrinsic reaction function of olefinic tpv and poor physical and chemical bonding with textile fibers.
Even in the process of high pressure compression molding of peeling samples, a single yam is completely embedded and mechanically locked in tpv, this low level of adhesion is observed.
In a closed woven composite structure, this condition of not being able to adhere to the textured fibers will not be conducive to enhancing the overall performance of the product.
Experiments of statistical design are used to develop new TPV at least 50 N/2 cm (15 pli)
Bonding with polyester and nylon fibers during melt processing.
At the initial stage of development, screen experiments were used to assign and quantify the factors and interaction effects of the TPV components.
The analysis of screening studies showed which factors had a significant impact on the properties of the adhesive.
The screening experiments used in the development of this TPV are: Plackett-Burman designs;
Department analysis design;
And analysis design
Burman design is very good at determining factor effects, and factor design predicts the importance of interaction terms in addition to factor effects.
The interaction effect is determined by the collaborative behavior of two or more variables.
The interaction item may have a significant impact on the attribute, although the afactor contained in the interaction item may not be as significant as the prior effect.
Once significant factors have been determined using the screening type experiment, the response surface design is used to optimize the tpv preparation.
Examples of response surface design are: Central composite design; Box-Design; and face-
A series of central composite designs were used during optimization and expansion
The textile can be bonded with TPV.
This technical overview focuses on the identification of key components that improve the adhesion of TPV to various Yam in themelt, as well as the final optimization studies used in the development of the grade TPV.
Discussion of the results five-factor fractional design is one of the screening studies designed to analyze the effects of various polymers and modifiers on tpv's ability to adhere to polyester and polyamide yam.
In this design, the fifth factor is intentionally confused with the interaction of the remaining four factors, thus being able to estimate the primary and first-order interaction effects.
The benefit of choosing this design is the reduction in combination and test time.
This design requires 16 recipes compared to a full-factorial design that requires 32 recipes.
Polymer modifiers A, B, and C are included to determine the significance of their contribution to adhesion, physical properties, and processing properties.
The term "polymer modifier" describes the thermofixed and thermoplastic components of the TPV, which may enhance the properties of the adhesive.
The levels of oil and filler were also evaluated to determine their impact on the adhesive properties, as well as possible improvements in the economics of formulation.
Table 3 shows the level of variables used for this screen analysis.
Table 4 summarizes the analysis of these five factors and the effect of their first-level interactions on the peel strength of the development TPV formula bonded to the woven "adhesive activation" polyester yarn line.
The adhesive activity that is usually used for polyester fibers rotary finishing is diluted water-
Epoxy solution based on fiber manufacturer application (ref. 1).
The response column in Table 4 shows the actual average value of tpv on the peel strength of polyester yarn in each trial (formulation)evaluated.
These trials were random During combination and testing.
Significant effects were determined by quantitative comparison of the size of the estimated effects assigned and by comparison with the overall mean of the studies listed in the estimated effects column.
The analysis in Table 4 shows that the size of the factor effect of polymer modifier A is 15. 6.
This value is large compared to other factors, interactions, and the average peel strength of all trials (32 pli.
The addition of polymer modifier A within the horizontal range selected for the design showed that with the increase of the level, the peel strength between tpv and woven Yam increased significantly.
It is important to note that the symbol of the estimated effect indicates whether the variable has a positive or negative effect on the response to the measurement.
A factor with significant negative effects will show a decrease in peelstrength as the level of factors increases.
After an increase in the level of polymer modifier B, another significant positive contribution to peel strength was observed.
This factor is considered significant, although the size of this value is less than the observed value of polymer modifier.
The increase in polymer modifier C, oil and filler levels had no significant effect on the overall ability of TPV to adhere to polyester yarn.
Some of the interaction terms have a significant impact on the overall average.
The combination of these factors is considered important or at least controlled in subsequent experimental designs to minimize variability in composite properties.
In these screening studies, the physical properties of tpv were also evaluated as responses to ensure that the engineering properties of various composites were maintained.
Response Surface designs are then constructed to optimize key variables such as polymer modifiers A and B, which are identified in the screening study as shown in Tables 3 and 4.
The central composite design is used to generate the response equation used to determine the optimal formulation.
For multi-response equations of two or three variables, it can be quickly optimized by layering the isograms of these equations.
By regression analysis of the data, the response equation is determined.
Equation 1 is an example of a regression equation for two independent variables. (1)Response = [A. sub. 0]+ [A. sub. 1]X + [A. sub. 2]Y +[A. sub. 11][X. sup. 2]+ [A. sub. 22][Y. sup. 2]+ [A. sub. 12]XYFigures 1-
3 is the profile map constructed from the data analysis of the central composite design for polymer modifier and B optimization.
The axes of these figures represent the actual weight percentage of these two components used in the TPV formulation.
One way to determine the best formula window for textile bondableTPV is through the inspection and coverage of the contour map. [GRAPHS OMITTED]Figures 1-
3 shows the tendency of adhesive peeling and final tensile strength as the levels of polymer modifiers A and B change.
Other responses were measured and included in the optimization analysis.
Visualization by using isograms is useful for developing intuitive and composite knowledge of these engineering properties.
Regression analysis is verified by using various statistical tests to ensure the accuracy of the results.
The plot was destroyed.
The difficulty with using this method is to visualize more than two formula windows for measuring responses or observations.
The expected function method is used to optimize the TPV formula of the multi-response equation at the same time.
Deringer andSuich mentioned the comprehensive treatment of this method (ref. 6)
Harrington (ref. 7).
In short, the observed physical properties and peel-off strength response equations are transformed into individual expectation functions optimized using a single variable technique.
These multiple responses are then embedded in an overall response function.
This overall expectation function is then analyzed to determine the optimal formulation area for the textilebondable TPV grade.
Tables 5 and 6 show the physical performance features of the three optimized tpv, which adhere to adhesive active polyester and polyamide yarns during melt processing.
In addition to the unique adhesion properties, these TPVs have excellent wear resistance and a very low specific weight.
The wear resistance of these materials is very beneficial to the application of engineering elastic materials such as hoses and belting, while the low specific ratio makes the product lighter in weight and lower in cost.
Table 6 shows a comparison of the adhesive properties of textile bonded TPV on several different yarns.
Compared to polyester Yam made using standard oil spinning, textile bondableTPV demonstrates excellent adhesion to adhesive-activated polyester fabric.
As mentioned earlier, the adhesive activity rotation finishing commonly used for polyester fibers is diluted water-
Epoxy solution based on fiber manufacturer application (ref. 1).
This type of spinning liquid increases the minimum cost for the overall structure, while increasing the adhesive peel strength of the textile sticky TPV.
The type of spinning solution on polyester fiber is very important for achieving a high level of adhesion to developmental tpv, while adhesion to polyamide 6/6 fiber is not related to surface finish.
Conclusion a series of new and high-performance cetpvs were successfully developed using experimental design for the adhesion of textile yarn in the process of melting processing.
Unlike traditional olefinic TPVs, they adhere very well to normal yarns and fabrics without using an adhesive system.
In the process of melting processing, the degree of adhesion to textiles far exceeds the minimum requirement of the peel strength of 42 N/2 cm.
This unique performance attribute opens up new markets and application opportunities for olefinic TPVs.
These bonded textiles tpv have the following properties compared to other engineered thermoplastic and thermosolid elastic materials: light weight;
Reduce the cost of finished products/reduce the proportion;
Excellent wear resistance;
Increased flexibility; matte finish;
In addition to elastic fatigue, the combination of these properties and properties allows the replacement of competitive thermofixed and thermoplastic elastic materials in an enhanced elastic structure.
Examples of enhanced tpvproduct include applications such as industrial hoses, lightweight conveyor belts, and fabric reinforced sheet products.
These novel TPVs are ideal for applications where cost savings are an important factor in product development. References(1. )I.
Skeist, adhesive manual, New York, Chapman and Hall, 1990. (2. )R. A.
Ryntz, coating adhesion to low surface free energy substrates in the automotive industry, polymer News, Volume 118, pp. 101-106, 1993. (3. )D.
Briggs, "surface treatment of polyolene" in "surface analysis and pretreatment of plastic and metal", New York, macmilan Publishing Company, 1982. (4. )R. A.
Ryntz, "latest progress in understanding the adhesion mechanism of automotive plastic paint", Proc. 25th Anniv. Symp. Polym. Inst. , pp. 308-30, 1994. (5. )M. D. Ellul and D. R.
Hazelton, "chemical surface treatment of natural rubber and ternary rubber thermoplastic rubber: Effects on friction and adhesion", Rubber Chemistry and Technology, Vol. 67, No. 4, Sept. -Oct. 1994. (6. )
Deringer and Suich, simultaneous optimization of several response variables, Journal of Quality Technology, Volume 112, No. October, 1980. (7. )Harrington, E. G. Jr.
"Desirable function" industrial quality control volume. 21, No. 10, 1965, pp. 494-498.