TWI569015B - Method for measuring polymer foam expansion and apparatus for use therein - Google Patents

Description

Method for measuring polymer bubble expansion and device therefor Field of invention

The present invention relates to a method for measuring the expansion of a polymer bubble and a device therefor.

Background of the invention

The technique of producing a foamed polymer product is a procedure that is close to the edges that are difficult to control. The technique of keeping the method in a controlled state involves many factors. For example, in the case of a PVC foamed product, such factors include the PVCK-value, the processing adjuvant used, the type and amount of lubricant, and the characteristics of the chemical blowing agent. The prediction of the expansion profile of the polymer formulation containing the test additive and content can be used to control the manufacture of the foamed polymer product. Currently available methods provide vesicles that can only expand at a certain time.

Summary of invention

The present invention is a method for measuring the expansion of a polymer bubble and a device therefor.

In one embodiment, the present invention provides a method of measuring the expansion of a polymer foam comprising: extruding a free hair containing one or more blowing agents a foaming polymer formulation; feeding the extruded formulation through a straight angle die to produce a shaped bubble body having a front portion of the bubble at the exit of the die, using a laser containing a laser driver a laser thickness measuring device for driving an upright positioner, wherein the laser system is coupled to the upright positioner to adjust an upright position of the laser, measuring a thickness of a shaped bubble located at the die nozzle; adjusting a speed of the motor drive Thus, the laser can be moved at a vertical displacement rate equal to the vertical displacement rate of the front portion of the bubble exiting the mold; and the thickness of the bubble is recorded, wherein the thickness of the shaped bubble is repeatedly measured every x seconds, where x Recording is from 0.05 to 0.15 and the thickness is measured in terms of time.

In an alternate embodiment, the present invention further provides an apparatus for measuring free bubble expansion of a polymer, comprising: an extrusion machine for extruding and forming a shaped bubble; wherein the extrusion The machine comprises a right angle die having a die nozzle; a laser measuring head connected to the upright positioning device for measuring the thickness of the formed bubble at or near the die nozzle; a connection to the upright positioner a motor driver device for adjusting a vertical displacement of the laser measuring head to synchronize a vertical bit rate of the bubble body exiting the die with a vertical displacement rate of the laser measuring head; a control for the motor driver a device for speed of the device; and a recording device capable of recording the thickness of the shaped bubble body with a time variation.

In an alternative embodiment, in accordance with any of the above embodiments, in addition to repeating at least one hundred times to measure the thickness of the shaped bubble, the present invention provides a method of measuring the expansion of a polymer bubble and a A device for measuring the free bubble expansion of a polymer.

In an alternative embodiment, the method further comprises In accordance with any of the above embodiments, the present invention provides a method for measuring the expansion of a polymer foam and a free bubble for measuring a polymer. Expanded device.

In an alternate embodiment, the present invention provides a measurement of polymer foams in accordance with any of the above embodiments, except that the free-foaming polymer formulation comprises polyvinyl chloride and one or more blowing agents. A method of expansion and a device for measuring the expansion of a free bubble of a polymer.

In an alternative embodiment, the present invention provides a measurement polymerization according to any of the above embodiments, except that the mold has a shape selected from the group consisting of a circle, an ellipse, a square, and a rectangle. A method of expanding a bubble body and a device for measuring the expansion of a free bubble of a polymer.

In an alternative embodiment, the method further comprises measuring the position of the front portion of the bubble in time, determining the vertical displacement rate of the front portion of the bubble, and automatically adjusting the speed of the motor driver to cause the laser to In accordance with any of the above embodiments, the present invention provides a method of measuring the expansion of a polymer bubble and a method for measuring, at a vertical displacement velocity that is the same as the measured vertical displacement velocity of the front portion of the bubble. A device for free bubble expansion of a polymer.

In an alternative embodiment, except for a circular die opening, the expansion of the bubble is measured as the square of the diameter of the bubble divided by the square of the diameter of the die nozzle, and the expansion of the bubble is from 1 to 50, according to the above In any of the embodiments, the present invention provides a method of measuring the expansion of a polymer bubble and a device for measuring the expansion of a free bubble of a polymer.

In an alternative embodiment, in addition to the apparatus further comprising a sensor for measuring the vertical position of the front portion of the time-varying shaped bubble body for determining the vertical displacement rate of the front portion of the shaped bubble body The present invention, according to any of the above embodiments, and a device for determining the vertical displacement of the front portion of the shaped bubble body is different from the control loop for controlling the motor driver device A method of measuring the expansion of a polymer bubble and a means for measuring the expansion of the free bubble of the polymer are provided.

In another embodiment, the present invention provides a method of measuring the expansion of a polymer foam, which essentially consists of extruding a free-foaming polymer formulation containing one or more blowing agents; The formulation is fed through a straight angle die to produce a shaped bubble body having a front portion of the bubble at the exit of the die, using a laser thickness of an upright positioner driven by a laser and a motor driver Measuring device (wherein the laser system is coupled to the upright positioner to adjust an upright position of the laser) measuring a thickness of a shaped bubble located in the die nozzle; adjusting a speed of the motor drive such that the laser can be equal to leave The vertical displacement rate of the vertical displacement rate of the front portion of the bubble moves; and the thickness of the bubble is recorded, wherein the thickness of the shaped bubble is repeatedly measured every x seconds, wherein x is from 0.05 to 0.15 and the thickness is Record with time as a variable.

In another embodiment, the present invention provides a device for determining free bubble expansion of a polymer, which consists essentially of: an extrusion machine for extruding and forming a shaped bubble; The extruder comprises a right angle die having a die nozzle; a thunder connected to the upright positioning device a measuring head for measuring a thickness of a shaped bubble located at or near the die nozzle; a motor driver coupled to the upright positioner for adjusting a vertical displacement of the laser measuring head to leave The vertical bit rate of the bubble of the mold is synchronized with the vertical displacement rate of the laser measuring head; a device for controlling the speed of the motor driver device; and a thickness of the shaped bubble that records the time as a variable Recording device.

10‧‧‧Extrusion machine

12‧‧‧Right angle mode

14‧‧‧Mold nozzle

16‧‧‧Formed bubble

18‧‧‧ Laser measuring head

20‧‧‧Upright positioner

22‧‧‧Motor drive

24‧‧‧VARIAC

26‧‧‧ computer

28‧‧‧Input cable

30‧‧‧Buckle belt components

To clarify the invention, one of the forms shown in the drawings is representative; however, it should be understood that the invention is not limited to the precise arrangements and instrumental arrangements shown.

Figure 1 is a schematic diagram illustrating one embodiment of the apparatus.

Figure 2 is a graph of cross-sectional expansion ratio versus time for a PVC formulation using three different hybrid endothermic/exothermic blowing agents; Figure 3 is a graph of cross-sectional expansion ratio versus time for a PVC formulation using three different endothermic blowing agents; Figure 4 is a graph of cross-sectional expansion ratio versus time for a PVC formulation using three different exothermic blowing agents; Figure 5 is a graph of cross-sectional expansion ratio versus time for a PVC formulation using three different blowing agents.

Detailed description of the preferred embodiment

The present invention is a method for measuring the expansion of a polymer bubble and a device therefor.

Method for measuring polymer bubble expansion according to the present invention The invention comprises: extruding a free-foaming polymer formulation comprising one or more blowing agents; feeding the extruded formulation through a straight angle die to produce a shape having a front portion of the foam at the exit of the die a non-contact measuring device that uses an upright positioner that is driven by a laser and that is driven by a motor driver (where the laser system is connected to the upright positioner so that one of the vertical positions of the laser can be adjusted) a thickness of the formed bubble of the mold nozzle; adjusting a speed of the motor driver such that the laser can move at a vertical displacement rate equal to a vertical displacement rate of the front portion of the bubble exiting the mold; and recording is time-variant The thickness of the foam, wherein the thickness of the shaped foam is measured every x seconds, wherein x is from 0.05 to 0.15 and the thickness is recorded as a time variable.

As used herein, "in the mold nozzle" means a position that is 0 to 1 mm away from the mold nozzle.

Extrusion of a free-foaming polymer formulation can be carried out using any suitable extruder, provided that the extruder can be equipped with a right angle die for forming a shaped bubble. Such extruders include, for example, single and multi-screw extruders. An extruder suitable for this extrusion step is a HAAKE POLYLAB conical twin screw extruder.

As used herein, a free-foaming polymer formulation includes any polymer formulation that is free to expand/foam upon leaving the mold. Examples of such polymer formulations include polymers selected from the group consisting of styrenated polymers, acrylates, polyolefins, polyesters, polyamines, polyvinyl chloride (PVC), chlorinated PVC And fluoropolymer; with one or more physical or chemical blowing agents. The blowing agent may be any one of a plurality of chemical blowing agents that release a gas upon thermal decomposition. The blowing agent or a mixture thereof or the like may be selected from a chemical containing a decomposable group such as an azo-containing, N-nitroso group, a carboxylate group, a carbonate group, a heterocyclic nitrogen group, and a sulfonium group. In general, they are solid materials that release gases (groups) when heated by chemical reaction or once decomposed. Representative compounds include azobiscarbamide and its derivatives as described in Plastic Additives Handbook, eds. R. Gachter, H. Muller, and PP Klemchuk, Hanser Gardner Publishers, Cincinnati, 1996, Ch. 16. Bicarbonate, anthraquinone derivatives, semi-calendar, tetrazole, benzo And boron hydrate. Examples of such blowing agents are: azodiamine, 4,4-oxybis(phenylsulfonyl), diphenylphosphonium-3,3-disulfoindole, triterpenoid , p-toluene, sulfonium sulfhydryl semicarbazone, 5-phenyltetrazole, isatoic anhydride, sodium hydrogencarbonate, and sodium borohydride. In addition, foaming can be produced by injecting a physical blowing agent into the extruder. Representative blowing agents include liquefied carbon dioxide, nitrogen, hydrocarbons, chlorofluorocarbons, hydrochlorofluorocarbons, and water.

The right angle mold that has been attached to the extruder and used to form a shaped bubble can have any suitable opening, or nozzle, shape. Such cross-sectional shapes may include, for example, circles, ovals, squares, and rectangles. The extruded polymer formulation can exit the mold and thus exhibit a cross-sectional shape of one of the mold openings. In the example of a mold having a circular opening, the thickness of the shaped bubble refers to the diameter of the formed circular shaped bubble. In the example of a mold having a square opening, the thickness of the shaped bubble means the length of one side of the square shaped bubble. In the example of a mold having an elliptical opening, the thickness of the shaped bubble refers to the short or long axis of the ellipse. Again, there is In the example of a rectangular open mold, the thickness of the shaped foam may refer to the short or long side of the rectangle. A multi-axis thickness measuring device can also be used to measure all shaft sizes simultaneously. The cross-sectional expansion ratio of any mold shape (the cross-sectional area at any particular time divided by the cross-sectional area of the mold opening) can be determined using this method.

The speed of the motor drive can be adjusted manually or automatically so that the laser can be moved at a vertical displacement rate equal to the vertical displacement rate of the front portion of the bubble exiting the die. In the case of manual adjustment, either or both of the vertical displacement rate of the laser and the vertical displacement rate of the front portion of the bubble exiting the mold can be manually monitored. In this case, the upright motor drive is activated when the bubble system is in the same plane as the bottom of the laser measuring device. The speed is manually adjusted using a variable self-coupled transformer (e.g., VARIAC) so that the front portion of the bubble can remain in the same plane as the bottom of the laser device. It can usually be achieved by 2 or 3 adjustments of the transformer. Similarly, in the case of automatic adjustment, the vertical displacement rate of the laser and the vertical displacement of the front portion of the bubble exiting the mold can be automatically monitored by electronic products and/or sensors that are well known in the art. Either or both of the rates. For example, the vertical bubble front speed and vertical laser speed can be measured by separate laser Doppler speedometers, and the speed of both can be synchronized by a control loop. Any type of non-contact speedometer, such as a laser Doppler speedometer, can be used to measure the vertical velocity of the front of the shaped bubble. Representative laser Doppler speedometers include laser Doppler speedometers from POLYTECH (Irvine, CA) and ZUMBACH ELECTRONIC AG (Orpund, Switzerland).

Multiple thickness measurements of the front portion of the shaped bubble are performed during at least one time from the exit of the mold until the maximum expansion is reached. These measurements can be made at intervals from 0.05 seconds to 0.15 seconds. The total measurement time can range from 1 second to 10 minutes.

All individual values and sub-ranges from 0.05 to 0.15 seconds are included herein and are disclosed herein; for example, from every 0.05, 0.07, 0.09, 0.11, or 0.13 second low limit to 0.07, 0.09, 0.11, 0.13, or 0.15 The upper limit is used for this thickness measurement. For example, the thickness can be measured at intervals from every 0.05 to 0.15 seconds, or the other, from every 0.07 to 0.13 seconds, or the other, from every 0.09 to 0.11 seconds.

In certain embodiments, the method further comprises calculating a rate of bubble expansion from the thickness of the bubble as a function of time. Since the method can measure a plurality of thicknesses with time as a variable, the rate of expansion of the bubble can be easily calculated by dividing the change in thickness after a certain time by the specific time.

In certain embodiments, the method of measuring the thickness of the shaped bubbles is repeated at least one hundred times.

In one embodiment of the method, the free-foaming polymer formulation comprises polyvinyl chloride and one or more blowing agents.

In some embodiments, the method further comprises measuring a position of the front portion of the bubble with time as a variable, calculating a rate of vertical displacement of the front portion of the bubble body and automatically adjusting a speed of the motor drive, whereby the laser can The movement is at a vertical displacement rate that is the same as the calculated vertical displacement rate at the front of the bubble. For example, the vertical can be measured by a separate laser Doppler speedometer. The velocity of the front of the bubble and the speed of the vertical laser can be synchronized by a control loop. The control loops and their components are well known and their examples are described in ttp://en.wikipedia.org/wiki/Control_loop, the disclosure of which is incorporated herein by reference.

In certain embodiments of the method, the expansion of the bubble is from 1 to 50 as measured by dividing the square of the bubble diameter by the square of the die opening diameter. All individual values and sub-ranges from 1 to 50 are included herein and disclosed herein; for example, the expansion of the bubble may be from the lower limit of 1, 10, 20, 30 or 40 to 10, 20, 30, 40 or 50. Upper limit. For example, the expansion of the foam may be in the range of from 1 to 50, or the other, the expansion of the foam may be in the range of from 10 to 40.

In an alternate embodiment, the present invention further provides an apparatus useful in the method of the present invention comprising an extruder for extruding and forming a foamed polymer formulation that provides a shaped foam; The extruder comprises a right angle die having a die nozzle; a laser measuring head coupled to the upright positioning device for measuring the thickness of the shaped bubble body at or near the die nozzle; a connection to the upright a motor driver device for positioning a device for adjusting a vertical displacement of the laser measuring head to synchronize a vertical displacement rate of a bubble body exiting the mold with a vertical displacement rate of the laser measuring head; a device for speeding the motor drive device; and a recording device for recording the thickness of the shaped bubble body as a function of time.

Extruders and dies that can be used in the apparatus of the present invention include those discussed above. The upright positioner can be any mechanical device used to vertically move the position of the item. For example, an upright positioner can include a rotating device A threaded rod that rotates with a motor drive such as a brushed DC motor, such as an electric drill or a stepper motor.

A laser measuring head that can be used in the device is a device that projects a laser onto the shaped bubble and the projection is electronically detected and converted into an electrical signal. There may be 2 or 3 spindle heads that can measure more than one size simultaneously. An alternative device measures thickness using two or more lasers by triangulation.

The apparatus for controlling a motor drive can include any method and/or apparatus for adjusting the speed of the motor drive, including, for example, a varistor and a variable self-coupled transformer. A description of the various devices used to control the speed of the motor can be found at www.en.wikipedia.org/motor controller.

Referring to Figure 1, there is shown an embodiment of a device that can be used in the method of the present invention. This is a device for measuring the expansion of a bubble of a polymer. The apparatus includes an extruder 10 and a right angle die 12 having a die nozzle 14. The polymer is extruded in the extruder 10 through the right angle die 12 and the die nozzle 14. Once formed away from the die nozzle 14, the shaped bubble 16 can have the shape of the die nozzle 14. A laser measuring head 18 is coupled to the upright positioner 20. The upright positioner is driven by a motor drive 22. As shown in Figure 1, the means for controlling the motor drive is VARIAC 24. The recording device shown in Figure 1 is a computer 26 having the necessary input cable 28.

Instance

The following examples are illustrative of the invention, but are not intended to limit the scope of the invention.

The equipment used in these representative methods was a HAAKE POLYLAB conical twin-screw extruder with a straight angle die (available from THERMO FISHER SCIENTIFIC, INC.). Table 1 shows the various zone settings for the extruder.

The free bubble polymer formulation used in this representative method was a PVC foam precursor mixture (MB1) having the composition shown in Table 2. Prior to extrusion, a processing adjuvant (SURECEL T-55 (available from The Dow Chemical Company), 10 PHR, which remained constant throughout all tests), and the blowing agent were bag blended with the parent mixture. Table 3 contains the chemical blowing agent groups used in each of the representative methods. A ZUMBACH USYS IPC-1 controller (available from ZUMBACH ELECTRONIC AG, Orpund, Switzerland) with a ZUMBACH ODAC laser meter (i.e., a laser measuring head) was used to measure the thickness of the shaped bubble.

The ZUMBACH ODAC laser meter is coupled to a stage that is movable in parallel with the shaped bubble via a threaded bracket. A rotary drill controlled by a VARIAC self-coupled transformer is used to raise or lower the laser gauge connected to the threaded bracket. The rotary drill is adapted to match the linear output of the shaped bubble by adjusting the VARIAC.

In order to concentrate the shaped bubble more properly, a higher expanded sample is obtained. A piece of Teflon was attached to the bottom of the laser gauge using a hook and loop tape. This type of adhesive strip that is optionally used is shown in Figure 1 as component 30. The measured value of the thickness of the shaped bubble body was collected every 0.1 seconds. These thickness measurements were collected from the ZUMBACH controller and analyzed using an Excel soft map.

The maximum thickness and time to maximum thickness are recorded, as well as the cross-sectional expansion ratio (CSER) and density values as defined below. These density values are obtained in accordance with ASTM Standard D792 "Standard Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement." These maximum thickness values are shown in Table 4. The cross-sectional expansion ratio (CSER) is a unitless measurement defined by the following equation: Where D ₁ is the diameter of the shaped bubble at time t and D ₀ is the diameter of the transverse nozzle. These graphs represent the different types of blowing agents (Exo, Endo, and Hybrid Endothermic and Exothermic) and the experimental sample 1 plots are used on all graphs. Comparison. 2-5 illustrate the expansion curves of the polymer formulation samples using each of the blowing agents shown in Table 3.

Figure 2 is a graph showing the cross-sectional expansion ratio of a PVC composition of a chemical blowing agent comprising a mixture of exothermic and endothermic components in a time-variant manner after the bubble exits the die opening. These hybrid exo/endo blowing agents are the most common blowing agents in PVC foams due to the combination of satisfactory properties of each of the blowing agent types.

Figure 2 shows that a mixture of exothermic and endothermic blowing agents provides both rapid and relatively high levels of expansion. Within the initial expansion section, the TRAMATO TSE 3140 has a slightly lower slope.

Figure 3 shows that the endothermic foaming agent has a much higher maximum expansion than the blowing agent consisting of a mixture of exothermic and endothermic types. Although these endothermic samples have a much larger total expansion, their initial expansion rate is much lower and a slightly higher density than a compound containing an exothermic material.

Figure 4 shows a comparison of the exothermic foaming agents with Experimental Sample 1 for reference. Its total expansion is lower than that of Experimental Sample 1, but the initial expansion rate is similar. The K-198 achieves a higher expansion than the HRVP01, which corresponds to its higher gas emission value (221 cc/g versus 190 cc/g).

Figure 5 shows the optimum type of blowing agent in a graph so that a direct comparison of the expansion characteristics can be observed.

The present invention may be embodied in other forms without departing from the spirit and scope of the invention. Therefore, when the scope of the invention is indicated, reference should be made to the appended claims.

10‧‧‧Extrusion machine

12‧‧‧Right angle mode

14‧‧‧Mold nozzle

16‧‧‧Formed bubble

18‧‧‧ Laser measuring head

20‧‧‧Upright positioner

22‧‧‧Motor drive

24‧‧‧VARIAC

26‧‧‧ computer

28‧‧‧Input cable

30‧‧‧Buckle belt components

Claims (9)

A method of measuring swelling of a polymer foam comprising: extruding a free-foaming polymer formulation comprising one or more blowing agents; feeding the extruded formulation through a straight angle die to exit one of the molds Generating a shaped bubble body having a front portion of a bubble body; using an upright positioner driven by a laser and a motor driver (wherein the laser system is coupled to the upright positioner to adjust a vertical position of the laser a laser thickness measuring device measures the thickness of the shaped bubble located in the die nozzle; adjusting the speed of the motor driver such that the laser can have a vertical displacement rate equal to the vertical displacement rate of the front portion of the bubble exiting the die Moving; and recording the thickness of the foam, wherein the thickness of the shaped foam is repeatedly measured every x seconds, wherein x is from 0.05 to 0.15 and the thickness is recorded as a time variable. The method of claim 1, further comprising measuring the maximum bubble thickness from the time-variant bubble thickness. The method of claim 1, wherein the free-foaming polymer formulation comprises polyvinyl chloride and one or more blowing agents. The method of claim 1, wherein the mold has a shape selected from the group consisting of a circle, an ellipse, a square, and a rectangle. The method of claim 1, further comprising measuring the The time is the position of the front of the variable bubble body, the vertical displacement rate of the front portion of the bubble body is measured and the speed of the motor driver is automatically adjusted so that the laser can be the same as the measured vertical displacement rate of the bubble body portion. The vertical displacement rate moves. The method of claim 1, wherein the expansion of the bubble body measured by dividing the square of the bubble diameter by the square of the diameter of the die nozzle is from 1 to 50. The method of claim 1, wherein the polymer foam has a cross-sectional expansion ratio of from 1 to 50. An apparatus for measuring free bubble expansion of a polymer, comprising: an extruder for extruding and forming a foamed polymer formulation capable of producing a shaped bubble; wherein the extruder comprises a a right angle mold of a die nozzle; a laser measuring head connected to the upright positioning device for measuring the thickness of the formed bubble body at or near the mold nozzle; a motor driver connected to the upright positioner Means for adjusting a vertical displacement of the laser measuring head to synchronize a vertical displacement rate of the bubble body exiting the mold with a vertical displacement rate of the laser measuring head; a device for controlling the speed of the motor driver; A recording device for recording the thickness of the shaped bubble body with time as a variable can be recorded. The device of claim 8 further comprising a sensor for measuring a vertical position of the front portion of the shaped bubble of time, for determining a vertical displacement of the front portion of the shaped bubble Rate setting And a control loop between the apparatus for determining the vertical displacement of the front portion of the shaped bulb and the apparatus for controlling the motor driver.