Heat-set Temperature Research Articles

Analyzing the dyeing behaviour of easy dyeable and regular polyester by the influence of different heat-setting temperature

The heat-setting effects of easy-dyeable polyester (EDP) have been investigated by comparing it with regular polyester fabric (PES). Using XRD analysis, the crystallinity and amorphousness of the easy-dyeable polyester and regular polyester fabric were assessed after 45 s during heat-setting of EDP and PES at nominal temperatures (120, 140, 160, 180, and 200 °C). The heat-set of EDP and PES fabric were dyed separately and competitively at temperatures ranging from 100 to 130 °C using S-type (C.I. Disperse Red 167) and E-type (C.I. Disperse Red 60) dyes. The color strength (fk ) and dye uptake were found to be lower at the heat-setting temperatures of 180 °C for PES and 140 °C for EDP. To ascertain the impact of varying heat-setting temperatures on PES and EDP-dyed fabric, the dimensional stability and GSM were assessed. When the heat set temperature was raised from 140 °C, the EDP fabric showed greater dimensional stability. On the other hand, the dimensional stability of untreated PES fabric (−4.2% lengthwise) and GSM (111 g/m2) gradually stabilized when the heat-setting temperature increased. However, the color fastness rating has improved after applying the heat-setting process for PES and EDP at 180o C and 140 °C, respectively.

Effect of heat-set temperature on the crease recovery behavior of cotton fabric dip-coated with shape memory polyurethane

The primary cause for low crease resistance in cotton fabric is the intermolecular hydrogen bonding rearrangement between the cellulose chains and inter yarn slippage. In this study, the crease recovery angle (CRA) of cotton fabric is enhanced by utilizing the shape memory effect of the shape memory polyurethane (SMPU). The SMPU was coated on cotton fabric via a simple dip coating method. The variation in CRA of SMPU coated fabric with temperature and load is monitored. The effect of heat-set temperature and thermomechanical variables - load and temperature on the shape memory performance of SMPU coated fabric is analysed. The results revealed that SMPU coated fabric heat-set at 140 °C displayed maximum shape recovery of 73.8% (at 10 N load and 50 °C programming temperature), which is retained after 10 washing treatments. In contrast, the memory performance deteriorated drastically in 100 °C SMPU/cotton (24% loss in CRA) and uncoated cotton samples (43% loss in CRA). The superior crease recovery is attributed to the molecular interaction between SMPU and cotton, which is affirmed by FTIR and Raman spectroscopic techniques. The shape memory effect of SMPU with concurrent crosslinking to cotton is responsible for the excellent crease recovery of fabric.

Study on Manufacturing PCT/PPS Flame Retardant Fiber by Sheath/Core Conjugate Spinning

In this study, fiber for wigs was produced by a sheath/core conjugate spinning machine using poly PCT (cyclohexanedimethanol terephthalate) as a sheath polymer and PPS (polyphenylene sulfide) as a core polymer. In order to withstand the high temperature of hot irons used in hair salons, the fiber was made of high heat resistant polymers. Also, an epoxy-type chain extender was added so that the MFI (melt flow index) of PCT, which had a lower melt velocity than PPS, could become similar to that of PPS. In addition, a phosphorus flame retardant was added to PCT, which has no flame retardancy, so that the limiting oxygen index (LOI) was raised to over 29. The strength and elongation of the manufactured yarn varied depending on the drawing method, draw ratio, and heat set temperature. The strength increased as the un-drawn yarn passed faster through the draw roller, and it also increased as the draw ratio increased. As the heat set temperature increased, the strength increased and the elongation decreased. The strength and the elongation of the PCT/PPS conjugate fiber were in the middle of the ranges of those of the single spun PCT and PPS fibers.

Field Observation of Cooling Energy Savings Due to High-Reflectance Paints

Cooling energy savings in a building with the roof coated with high-reflectance paint are examined. It is difficult to recognize such savings using the data observed hourly. Among the factors assumed to affect cooling energy load are: (1) internal heat generation, (2) set temperature, and (3) weather conditions. By analyzing the relationship between indoor-outdoor air temperature difference (averaged) and electric power consumption (integrated) of the air conditioner in the building over a day, the reduction in electric power consumption due to the use of a high-reflectance paint coating is estimated at approximately 72 Wh·m−2·day−1.

Physical properties of para-aramid/nylon hybrid air textured yarns for protective clothing

The physical properties of a para-aramid/nylon hybrid filament, such as the denier, tensile properties and thermal shrinkage, were examined according to the processing conditions of air-textured yarn (ATY), such as the yarn speed, air pressure, heater temperature, and overfeed ratio. The instability for identifying loop formation on the yarn surface was also measured and discussed. The yarn linear density increased with increasing overfeed of the core and effect and air pressure. The tenacity decreased with increasing core overfeed and air pressure, whereas the breaking strain increased. The initial modulus of the hybrid filament decreased with increasing core overfeed, air pressure and heat-set temperature of the heater. The instability of the hybrid ATY yarns increased with increasing heater temperature. The dry thermal shrinkage increased with increasing core overfeed, and the wet thermal shrinkage decreased with increasing effect overfeed. The core overfeed was found to be a key factor affecting the physical properties of the para-aramid/nylon hybrid ATY, whereas the air pressure was found to influence only the yarn mechanical properties. In addition, the heating temperature affected the instability of the para-aramid/nylon hybrid ATY. These results show that a low core overfeed and high effect overfeed are needed for good thermal dimensional stability to wet and dry heat during thermal treatment processes.

Thermal Simulation and Experimental Study on Tire Building Machine Hot Knife

To tire building machine hot knife , for example, the heat set temperature, flank contact temperature and flank edge temperature were determined and analysis, finite element method for heat transfer simulation calculations. After experimental verification, simulation and prediction of flank and edge temperature consistent with the measured data. Experiments show that the temperature can effectively control the heat source to control the temperature of a specific area, so not for the excess heat to meet the processing requirements to achieve efficient use of energy.

Effect of Distributor Geometry on Crimp Contraction of PET Side-by-side Bicomponent Fibers

Abstract The effect of distributor geometry on crimp contraction in the melt spinning and drawing of polyethylene terephthalate (PET) side-by-side bicomponent fibers was studied. Three different distributors located on top of the spinneret were designed to change curvature ratio of a side-by-side cross-section of bicomponent fibers. Regular and modified PET were selected to make latent crimp yarns. Spinning and drawing conditions were changed to choose the effective variables heat set temperature and draw ratio. Crimp contraction increased with increasing draw ratio and decreasing heat set temperature. Die geometry had a significant effect on crimp contraction by changing the curvature ratio of the cross-section. Under the same spinning and drawing conditions, the crimp contraction with higher curvature ratio was larger.

Effects of spinning and drawing conditions on the crimp contraction of side‐by‐side poly(trimethylene terephthalate) bicomponent fibers

AbstractThe crimp properties in the melt‐spinning and drawing processes of side‐by‐side bicomponent fibers with poly(trimethylene terephthalate)s (PTTs) of different viscosities were studied. Two PTTs of different intrinsic viscosities (1.02 and 0.92) were selected to make latent crimp yarn. The spinning and drawing conditions were changed to investigate the relation between the process conditions and crimp contraction. An orthogonal array was used to rule out the weak variables. The draw ratio, heat‐set temperature, and portion of high‐viscosity PTT were selected as variables having an effect on the crimp contraction. An analysis of the effects of the spinning and drawing conditions on the crimp contraction showed that the draw ratio was the most critical variable. Increasing the draw ratio caused a difference in the shrinkage between the two parts of PTT and caused the self‐crimping of the bicomponent fibers. Although changing the heat‐set temperature and the portion of high‐viscosity PTT did not produce a dimensional change, the crimp contraction varied with those variables. As the heat‐set temperature and the high‐viscosity portion increased, the crimp contraction increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1322–1327, 2006

PBT/PET conjugated fibers: Melt spinning, fiber properties, and thermal bonding

AbstractThis work examines the PBT/PET sheath/core conjugated fiber, with reference to melt spinning, fiber properties and thermal bonding. Regarding the rheological behaviors in the conjugated spinning, PET and PBT show the smallest difference between their melt‐viscosity at temperatures of 290°C and 260°C respectively, which has been thought to represent optimal spinning conditions. The effect of processing parameters on the crystallinity of core material‐PET was observed and listed. In order of importance, these factors are the draw ratio, the heat‐set temperature, and the drawing temperature. The crystallinity of sheath material‐PBT, however, can be considered to be constant, independent of any processing parameters. The bulk orientation, rather than the crystallinity of PET core, dominates the tenacity of PBT/PET sheath/core fiber. Moreover, heat‐set treatment after drawing is recommended to yield a highly oriented conjugated fiber. With respect to thermal bonding, PBT/PET conjugated fibers processed via high draw ratio but low‐temperature heat setting can form optimal thermal bonds at a constant bonding temperature of 10°C above the Tm of PBT.

Structural Modification of Polyester Shin-Gosen by the Treatment in Supercritical Carbon Dioxide Fluids

Polyester Shin-gosen fibers were heat-set and subjected to supercritical CO2 fluid treatment (SFT, 125 °C, 25 MPa, 60 min) or pressurized water treatment (PWT, 130 °C, 60 min), where the shrink behavior and the mechanism were compared. As for PWT, heat-set temperature over than 160 °C was enough for the suppression of shrinkage lower than 2%. On the contrary, as for SFT, the shrinkage could not be suppressed at the same level even in the case for the fibers heat-set at 200 °C. The large shrinkage seems to be brought about by the migration of oligomer through SFT. The oligomer migration lowered the tensile modulus, and gained the elongation of the treated fibers. However, the tensile strength of the fiber was hardly affected by SFT.

Heat setting of stretched and microvoided PE/CaCO3 films

AbstractCalcium‐carbonate‐filled linear low‐density polyethylene (LLDPE) films play an important role in the hygienics market because these materials allow for the diffusion of water vapor (breathability) and retain a liquid barrier while providing a barrier to liquids. This is achieved when properly formulated composites are stretched to create pores. There are many important issues surrounding this technology; this report focuses on the effects of poststretching heat‐set treatment on moisture vapor transmission rate (MVTR), dynamical mechanical thermal analysis (DMTA), tensile heat distortion temperature (THDT), and differential scanning calorimetry (DSC) thermal transitions of the porous film properties. Eastman personnel provided the LLDPE/CaCO3 breathable films for this study. In general, the film properties were insensitive to heat‐setting time beyond that of 1 min. This result suggests that the molecular reorientation and recrystallization associated with the changes in film properties occur rapidly. Properties were, however, strongly sensitive to the heat‐set temperature when MVTR decreased and DMTA properties [specifically storage modulus (E′) and the α‐transition temperature] increased as the heat‐set temperature increased. This is believed to have been mainly caused by pore closure and the annealing of crystalline regions. The heat‐set temperature was easily detectable by DSC techniques when a thermal transition was apparent at the applied temperature, and changes in the heat of fusion for the sample could be observed. Ultimately, the changes in the properties of these porous films were related to changes in the molecular orientation and crystallinity of the matrix in combination with changes in the void structure of the composite. In particular, changes in E′ could be related to these separate effects. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2454–2471, 2001

Measuring Nylon Carpet Yarn Heat History by Remote NIR Spectroscopy. Part II: Applying Remote Fiber Optic NIR Techniques to the Manufacturing Environment

Part I of this series demonstrated the Near-IR (NIR) method of determining the heat-set temperature (HST) of carpet yarn on bobbins in the laboratory, using a remote fiber optic probe. Part II describes an at-line NIR technique to determine the HST of carpet yarn bobbins at three manufacturing sites. At-line NIR measurement of HST is expanded to evaluate the influence of machinery and yarn processing factors, environmental factors, and quality differences. Optimized Suessen and Superba HST at-line NIR calibrations are developed in the laboratory and successfully transferred and verified on the manufacturing floor. Very good agreement is obtained between the stated HSTS and NIR-determined HSTS for samples with a wide range of HSTS and routine production samples, which exhibit quality differences in manufacturing. The major influence on NIR-determined HST results is the temperature and %RH in the manufacturing area; the NIR calibration can be readily adjusted with a control bobbin to offset these environmental effects without loss of method accuracy. An analytical methodology is presented for developing and transfering (verifying and validating) NIR measurements from a laboratory to an at-line analysis in the manufacturing area. Operational concerns and other procedural details include sample matrix effects, data treatment, temperature and environmental impacts, instrument parameters, and details of the experimental process.

Measuring Nylon Carpet Yarn Heat History by Remote NIR Spectroscopy

Heat setting of nylon carpet yarns is one of the most critical processes in carpet manufacturing. The temperature at which the yarn is heat set—the heat-set temperature (HST)—is one of the most important operational variables in the process. Previous investigations with laboratory, bench-top, near infrared (NIR) reflectance instrumentation had shown NIR to be a simple, rapid, and accurate laboratory technique for measuring the HST of nylon carpet yams. The potential of NIR for measuring the HST/heat history of nylon carpet yarns directly on the carpet yarn bobbin and in the manufacturing area is evaluated in a two-phase program. In this paper, Phase One—the evaluation of remote fiber optic sampling systems and the development of a laboratory measurement of HST/heat history directly on the bobbin—is presented and discussed. Nylon 66 yams are heat set by both the Suessen and Superba methods over wide HST ranges. NIR calibrations for HST are developed and validated with two remote fiber optic sampling systems—an interactance probe ("Probe") and a remote reflectance head ("Head"). Excellent agreement is obtained between the stated Suessen and Superba HSTs and the NIR results for both fiber optic sampling systems, with high R2 values (normally >0.9) and low residuals (standard deviation of differences, SDD) of normally <3° for both systems on both heat-set methods. The Probe sampling system is the best overall system for at-line measurements, with low sampling system weight, simpler operation, faster analysis time, and increased flexibility. The Head sampling system is the best overall system for on-line measurements, where its superior accuracy can be optimized.

Correlation of thermally stimulated current and blow molding condition in poly(ethylene terephthalate) bottles

Thermally stimulated current (TSC) was used to study molecular relaxations in polyethylene terephthalate (PET) bottles. Unstretched PET film, which was used as a model for the bottle preform, exhibited two peaks at 77 and 90°C that correspond to the α and ρ relaxation processes, respectively. The bottles exhibited only the ρ relaxation, which is located within the temperature range for blow molding PET bottles. The α peak is associated with the main glass transition temperature (Tg) and the ρ peak may be associated with a second Tg. The second Tg is attributed to a “constrained state,” which shows dipolar behavior. Heat-shrinkage behavior was examined at 90°C. The maximum TSC (Im) of the ρ peak decreased with increasing heat set temperature, and with decreasing shrinkage. Bottles blown at 113°C showed a lower Im and shrinkage than those blown at 103°C for equivalent heat set temperatures. The higher blowing temperature allowed a higher stretch speed that produced higher crystallinity bottles with self-heat generation during rapid deformation. A relationship between the shrinkage mechanism and the dipole relaxation was proposed.

Physical and microstructural effects of heat setting in polyester films

AbstractThe effects of a controlled heat‐setting treatment on the properties and microstructure of biaxially stretched poly(ethylene terephthalate) (PET) and poly(ethylene‐2,6‐naphthalene dicarboxylate) (PEN) films are described. Substantial changes in crystalline fraction, crystallite size, glass transition temperature and significant enhancement in dimensional stability are observed for both film types upon increase in heat‐set temperature. A distinct melting peak in the vicinity of the heatset temperature, observed in differential scanning calorimetry thermograms for both materials, is shown to be an effective marker of the heat‐setting process underlying the dual nature of the morphology of the heat‐treated films. We also observe that the PET films undergo significant molecular realignment on heat setting, while the orientation of the PEN films is only weakly modified by the heat‐set conditions. A morphological transition is detected for both films at high heat‐set temperature (THS*) near the onset of the primary melting range, marking a qualitative change in the physical response of the biaxially oriented films; Measurable drop in planar orientation and glass transition temperature, and a sharp rise in crystallite size are noted for films heat‐treated above THS*. The morphological models of previous workers (Schultz et al. and Fischer and Fakirov), invoking the idea of fibrillar‐to‐lamellar transformation, are used to explain some of our observations.

The Effects of Degree of Stretching on the Properties of Heat Set Biaxially Stretched Naphthalate-Containing Polyester Films

The thermal and gas barriers of PET may be enhanced by heat setting. Those properties also may be improved by modifying PET with PEN either as a copolymer or a blend. The effects of degree of stretching and heat setting on density, shrinkage, and oxygen permeability of biaxially stretched films of PET, PET-N8 copolymer (PET modified with 8 mole percent naphthalate), and 10.6 and 25 wt% blends of PEN-T8 (PEN modified with 8 mole percent terephthalate) with PET have been studied. For all compositions, density increased with increasing degree of stretching and with increasing heat set temperature. At the highest heat set temperature (180°C) the density reached was almost independent of the starting stretch ratio. Shrinkage and oxygen permeability decreased with increasing naphthalate content and increasing heat set temperature with the 3.5 x biaxially oriented 25% blend composition (non-heat set or heat set) having oxygen permeability about 40% less than similarly oriented PET.

Determining the Heat-Set Temperature for Poly(ethylene Terephthalate) Carpet Yarn with Near-Infrared Reflectance Spectroscopy

Near infrared reflectance spectroscopy can be used effectively to predict the heat- set temperature of poly(ethylene terephthalate) carpet yams in the Suessen process with customized calibration. Reflectance at three wavelengths used with a linear regression model is sufficient to predict the desired property (heat-set temperature) accurately. The coefficients of fit found in these sets are approximately 0.978. The justification for the wavelengths selected is explained on the basis of previous work and the experimental data.

Effects of Suessen Heat Setting Variables on Streaks in Finished Nylon Carpet

The effects of dry heat setting conditions on streaks in finished carpets made from nylon 66 staple yams are considered. Two different polymers were subjected to con trolled variation in heat-set temperature, residence time, and chamber steam pressure on a Suessen machine according to a factorial design. Yarns from some of the items were made into finished carpets, and other items were implanted into these carpets using two adjacent creel positions. Streak intensity grades were assigned to these im plants, and then an empirical model was fit to the data relating streak intensity to the differences between the background and implant items in heat setting conditions. Streaks caused by variation in heat setting conditions are associated with differences in dye uptake rather than with physical or textural differences between tuftlines. If the Suessen is operated at a nominal temperature of 200°C, then surprisingly large dif ferences in heat setting conditions are required in order to cause an objectionable streak. Furthermore, the effect of heat-set temperature differences on carpet streaks depends on the dyeing system used. For a continuous dyeing system, which has a dye uptake minimum at 200°C, any tuftline-to-tuftline heat-set temperature variation from 200°C causes dark streaks. On the other hand, the Beck system has a linear rather than a U-shaped dye response to heat-set temperature, and increases considerably above 200°C cause light streaks when that tuftline is implanted within a group of tuftlines having experienced a 200°C temperature.

Structural Properties of Nylon 66 Carpet Yarns Observed with Near Infrared Analysis

Heat significantly influences the supermolecular structure of nylon, which results in changes in the fibers' chemical and physical properties and the morphological re sponse of the yam systems during further processing. The near infrared analysis (NIR) technique has been used extensively to measure the heat-set temperature of nylon yams. Previous investigations have studied the effect of changes in heat history on the NIR spectrum of nylon carpet yams from a spectroscopic approach, in which the wavelength assignments and the rationale for specific wavelengths used on the heat set temperature NIR calibration equations were presented. In this paper, a crystallo graphic approach is used to examine the effect that changes in the heat history of Suessen heat-set nylon 66 carpet yams have on the NIR spectrum and the heat-set temperature NIR calibration equations, and various crystalline, thermal, and laser light scattering parameters of the Suessen heat-set nylon 66 yarns are measured. The NIR spectrum is responding to changes in the crystalline perfection of the nylon 66 polymer with changing temperature, specifically to changes in the C—H stretches in the Van der Waals plane. Agreement between the results of the various measurement techniques (crystalline, thermal, light-scattering, NIR) is excellent. A definite change in morphological response occurs at ∼190°C, which coincides with the Brill transition of nylon 66. The slight deviation from linearity in the NIR response below the heat set temperature of 190°C is due to the Brill transition.

NIRA Primary Wavelength Investigations of Nylon Yams

Near infrared reflectance analysis (NIRA) is a rapid and accurate technique for measuring the heat set temperature of nylon carpet yams. Several investigations on Suessen heat set nylon 66 yams have yielded empirical prediction equations based on reflectance at three wavelengths, with 2130 nm being common to each investigation. Investigations of the derivatives of the NIRA spectra obtained from various Suessen heat set nylon 66 samples and comparisons of the NIRA spectra to other polymers have yielded new information on probable wavelength structural assignments and the probable rationale for the 2130 nm wavelength's commonality. The 2130 nm wave length is caused by a combination of the C — H stretch/C=O stretch combination and N — H deformation/N—H stretch combination, the 2100 nm wavelength is caused by C = 0 stretch combinations, and the 2270 nm wavelength is caused by various CH/CH2 stretches, bends, and deformations. The 2100 and 2130 nm wave lengths are the primary combination for correlating the crystallinity changes occurring with changing heat set temperature in nylon 66 carpet yams. Derivative spectra indicate that a consistent "slope" change occurs in the original spectra from 2100 to 2130 nm, with increasing absorption at 2100 nm and decreasing absorption at 2130 nm with increasing heat set temperature. This slope change is the driving force in the NIRA's ability to measure the heat set temperature.