JPS6318522B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In order to attach an inclined windshield glass and a rear window glass to a car body, a high viscosity moisture-curable polyurethane sealant is extruded in a string around the glass periphery using a pump, and the welded flange of the car body opening is attached to the welded flange. A glass plate is placed on the wall, and the sealant is not pushed sideways by the weight of the glass, and the glass is supported only by the string-like sealant. By doing this, a rubber dam is created to support the weight of the glass. Both sides of the string-like sealant are directly exposed to the humid atmosphere without the need for the sealant.

A windshield glass and a rear window glass must be installed on a car body that is moved along an automobile body assembly line.

On modern assembly lines, car bodies are fed continuously, and the installation of the glass panes typically takes about an hour.
The event takes place over a limited period of time, with 60 cars running, approximately one every minute.

One method of attaching a glass plate is to wrap a string-like grooved rubber around the periphery of the glass plate and mechanically fasten it to form a seal. Grooved string rubber is made by extruding vulcanized rubber into a certain shape. This method is expensive and has the disadvantage that the glass is simply attached to the vehicle body without making any contribution to the strength of the vehicle body.

Mechanically installing the glass plate has the advantage that everything handled at the installation site is dry and clean, and the operator can dispose of it quickly without worrying about contaminating the glass plate or the surrounding vehicle body. , other methods of attaching glass plates are also used.

A method of directly attaching a glass plate is also used.
In this method, the periphery of the glass plate is directly fixed with adhesive to a metal plate flange that is welded and attached to the glass attachment part of the vehicle body. The adhesive used is elastic and helps bond the glass pane and welded flange together to increase the strength of the vehicle, reducing the amount of other metal materials needed to maintain strength. Contributing.

In detail, in this direct glass installation method, a dam made of vulcanized rubber is fixed with adhesive to the inner peripheral edge of the glass plate where it is attached to the car body, and a polysulfide composition sealant is usually used. , a semi-fluid sealant is pumped by the operator to the outside of the rubber dam around the periphery of the glass pane. Next, the glass plate is lifted mechanically or manually and attached to the welded flange using a sealant to adhere it to the vehicle body. Since the windshield and rear window glass are slanted considerably inward relative to the top surface of the vehicle, the weight of the glass panes is applied directly to the flanges. A spacer, which is later removed, is placed in the lower edge of the glass plate to prevent the glass from sliding downward, but the slanted position of the glass plate places the weight of the glass on the flange. The rubber dam serves to support this force and prevents the sealant applied to the periphery of the glass plate from being pushed out, and is provided for this purpose. The rubber dam is adapted to deform so that the sealant completely adheres to the flange.

Further, the rubber dam is used to prevent sealant from flowing inwardly from the periphery of the glass pane during application of the sealant. Even so, if the operator operating the nozzle is in a hurry, the sealant can flow over the rubber dam and into the windshield. Particularly when going around the corners of a glass plate, a considerable amount flows out, making things uncomfortable. This can be corrected by manually stroking it with a spatula, but if there is too much sealant, it will be pushed out to the area around the windshield mounting opening even if the glass plate is supported by the rubber dam. Since the roof of the car body is near where the glass plate installation work is being done,
If contaminated with sealant, it will need to be cleaned and may need to be replaced. A partially unsuitable sealant will cause leaks.

Increased seal strength is obtained when the polyurethane sealant/primer system of De Santis US Pat. No. 3,779,794, cited herein, is used in place of prior art polysulfide sealants. Specifically, the DeSantis sealant consists of a moisture curable crosslinked polyurethane prepolymer made by the reaction of a mixture of diols and triols with excess diisocyanate. To produce a sealant, 0.01 to 3 parts of a catalyst for moisture curing reaction is added to 100 parts of such a polyurethane prepolymer in order to adjust the viscosity to have appropriate fluidity and sag.
Mix up to 135 parts of filler, up to 20 parts of plasticizer, and up to 20 parts of organic solvent. Particularly preferred as catalyst is di(phenylmarkylic)dodecyl succinate. Carbon black is particularly preferred as a filler, and silica may also be used. Preferred plasticizers include diacetyl phthalate, tricresyl phosphate, and dibutyl phthalate, and preferred solvents include methyl ethyl ketone and ethyl acetate.

Such sealants are preferably used over isocyanate-reactive primers, also disclosed in the DeSantis patent. The aforementioned primer is made of a mixture of an aliphatic isocyanate compound or a silane compound and a film-like polymer resin such as chlorinated rubber or vinyl chloride, a polyacrylic resin, or a polyester resin.

The viscosity of the aforementioned sealants can be adjusted by varying the ratio of plasticizer and solvent to the amount of polyurethane polymer and filler. Increasing the amount of polyurethane polymer and filler increases the viscosity. For economically conventional direct glass installation methods, the viscosity has been determined by the time required to extrude 20 grams of sealant through a 0.104 inch outlet under a pressure of 60 pounds per square inch. In the conventional example, a sealant having a viscosity that required 30 to 40 seconds to extrude 20 grams of sealant under the above conditions was used.

The use of such sealants in direct glass installation methods can increase seal strength, but the need for cleaning increases when the sealant is used in direct installation of automotive windshields and rear windows. . If the sealant were to adhere to the roof of the vehicle for any reason, removal of the sealant would be extremely difficult or impossible due to the increased seal strength. Although the viscosity of the sealant is adjusted so that it does not sag or flow under the influence of gravity, conventional methods nevertheless cause it to flow on the periphery between the edge of the glass plate and the rubber dam. That is,
The viscosity of the sealant is largely liquid in nature.
When such conventional low viscosity moisture curable polyurethane sealants are extruded through a nozzle, they have a shiny, wet feel and will stick to the operator's hands and other objects no matter how lightly touched. Problems with direct glass attachment methods using polysulfide sealants remain, and the high seal strength of the otherwise desirable polyurethane materials greatly increases the messiness problem.

In the present invention, a moisture-curable crosslinked polyurethane prepolymer, catalyst, filler, plasticizer, and solvent are mixed as in the DeSantis patent, and the viscosity is such that the sealant can be removed from a 0.104 inch outlet under a pressure of 60 pounds per square inch. The ratio of solvent and plasticizer to prepolymer and filler was adjusted so that the time required to extrude 20 grams was 300 seconds or more. Such compositions have a viscosity that allows uncured strands of precise shape to be extruded from a nozzle with sufficient pressure. These highly viscous sealants are matte and can even be touched by the operator's hands. The extruded string-like body can be corrected manually if necessary, and has cohesiveness to the extent that the bottom part will not be plastically deformed by the weight of the glass itself. If the string extruded from the nozzle becomes distorted around the edge of the glass, it can be corrected manually. It doesn't stick to anything; you have to press it with your hand to make it stick.

The sealant used in the present invention can be made by the method disclosed in the DeSantis patent, in which case the ratio of plasticizer and solvent can be adjusted to the amount of polyurethane polymer and filler. However, just to be sure, a specific example is as follows.

That is, in Example 1 of the above patent, 106.9 pounds of diphenylmethane 4-4' diisocyanate, preheated to 120°C, is placed in a jacket reactor under nitrogen, and to this is added 415.7 pounds of polypropylene ether diol having an average molecular weight of about 2000. The mixture is heated to 180°C and maintained at this temperature in order to remove the hydroxyl groups and provide 3.5% by weight of unreacted isocyanate groups based on the reaction product.

The mixture is then cooled to 120 ml and 189.9 pounds of polypropylene ether triol having an average molecular weight of 4200-4800 and 285 pounds of chlorinated biphenyl containing 42% by weight chlorine are added. moreover,
25 grams of stannous octoate (catalyst) are added to this mixture and maintained at 140 ml until the proportion of free isocyanate groups in the resulting crosslinked product is 1.3%. It is then cooled to 90°C and 2.5 pounds of diethyl malonate is added to block any remaining free isocyanate groups.

Prepolymers thus produced 647.94
28 inches of mercury in a vacuum mixer, remove the vacuum in a nitrogen atmosphere, add 186.15 pounds of furnace black, 132.3 pounds of thermal black, and add 2.75 pounds of diethyl malonate under nitrogen.
27.49 pounds of toluene as a 21 weight percent solution in heavy naphtha, and 3.37 pounds of di(phenylmarkylic) dodecyl succinate. The mixture is stirred until homogeneous and then released into a container under nitrogen.

In order to obtain a sealant having the viscosity required by the present invention, in the above example, in the third step, dry furnace black, thermal
Black + Dry Clay 170
Just add pounds.

Using the direct glass attachment method of the present invention using a high viscosity sealant, a rubber dam is not required.
After the extruded string-like body is released from the restraint by the rubber dam, the entire side surface, that is, the end surface, is opened so that it is hardened by surrounding moisture.

The resulting seal strength achieved by the high viscosity sealants described above is usually defined as the resistance force that prevents the glass pane from being dislodged when a vehicle is struck at a constant speed. It was recognized that it fully complies with the current specifications. Its strength is comparable to or better than that obtained with traditional direct glass attachment methods using DeSantis' low viscosity sealants.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a portion of an automobile assembly line in which the line passes through a glass plate installation area, where a glass plate is installed, and then passes through a shower room 2 where a watertight test is performed. The side windows and rear windows are already installed on the car body, and a windshield needs to be installed in the front.

A worker, designated 3, is applying an isocyanate-reactive surf-spring primer to the peripheral edge of a windshield, designated 4, which is held by a suction cup on turntable 5. There are no particular problems in applying this primer. The equipment designated 6 is that commonly used for applying primers. After applying the primer, the operator 3 places the glass plate on a rotary drying table 7 and quickly dries the primer.

FIG. 2 shows a turntable which carries a glass plate which is primed in the form of a thin layer or coating 8 on its periphery. The method of applying the primer is common practice and will not be discussed in detail here, but the primer is usually applied using a spray gun with a brush that prevents the primer from deviating from the appropriate area around the periphery of the glass plate. be done.

The procedure described so far may be the same as that used to attach a windshield directly using a rubber dam using a conventional sealing system.

The location where the sealant is applied is indicated by reference numeral 11, but any conventional sealant may be used. However, the difference here is that there is a pump system with sufficient capacity to process the high viscosity sealant required by the present invention at an appropriate rate.

In FIG. 4, a can 12 containing a polyurethane-based moisture-curing sealant made airtight and waterproof with a plastic lid 13 is inserted into a piston-shaped part made rigid by a plunger 15 of a suitable pump device. 14 shows the state in which it is pressed down.

However, in this case, the sealant 16 in the can is formulated to have a high viscosity as described above. This can be done by adjusting the viscosity using a filler to obtain the above-mentioned high viscosity sealant.

In FIG. 4, the operator operates the trigger 18 of the handle 19 to push out the sealant from the nozzle 17, and since the pump device is a known one, details are not shown.
The operation of the sealant pump is electrically controlled by a switch via a cable 20.

The viscosity required to practice the invention can be precisely determined experimentally. As shown in FIGS. 5 and 6, the string-like sealant 16 is fed out from the pump.
A has a flat bottom surface 16b that rests on the primer at the periphery of the windshield. The string-like sealant is extruded by the pump, and once it is extruded from the nozzle 17, the sealant has properties similar to hardened string-like rubber. The amount of filler put into the sealant is determined so that when the sealant is extruded into a string, it is uncured or undried immediately after extrusion, is matte, has sufficient cohesiveness, and does not fray when at least lightly touched. , should result in a well-defined extrudate. Other than its shape, it should resemble the rubber tape used to mechanically fit glass sheets.

To further explain the required viscosity, Fig. 8 shows a flange 2 point welded to an automobile body.
1 shows the state in which the windshield is brought close, and in FIG. 10, force is initially applied to support the glass plate in the direction of arrow 22 so that the entire weight of the glass plate is not applied to the string-like sealant 16a, but then Otherwise, the entire weight of the glass plate is the string-like sealant 16a.
It shows that it can be supported by The viscosity of the sealant is selected so that the strands of sealant are not substantially extruded laterally due to plastic deformation. In addition to the weight of the glass, if necessary, first press the glass plate by hand to ensure that the sealant strings adhere to the flanges. Because it has flexibility or rubber-like elasticity,
The string-like sealant also conforms to the irregularities of the surface of the flange 21 and deforms slightly around the edges of the glass plate.
If the sealant is adjusted to have a viscosity necessary to support the weight of the glass plate 4, it can be elastically deformed sufficiently to contact the outer surface of the flange 21 over the circumferential surface that requires sealing. It has uncured rubber-like properties.

Modern car body designs require flanges that slope backwards, and in modern cars in particular, this slope is so pronounced that most of the weight of the glass plate exerts pressure on the flange, and this force The string sealant must be supported without extruding.

In Figure 1, the car 1 on the far right is traveling without a windshield installed, and the worker 2
2 is in the position shown and arrow 2 is pointing to the next car on the left.
The operator is shown preparing to install the windshield by hand, as shown at 3, where the operator holds the glass pane in a suction cup retainer 24, although a mechanical retainer could also be used. ing.

As shown in Figure 10, when a windshield is attached and the weight of the glass is supported by the string sealant 16a pushed out by the pump, its cross section will be either triangular with a flat surface against the glass or flat. Note, however, that in both cases all sides of the string sealant are exposed to the humid atmosphere, which differs from conventional practice. Due to its ability to cure with atmospheric moisture, this high viscosity sealant cures more quickly than in traditional direct glass installation operations. When a car is placed in the shower room 2 for water leakage testing, the water from the shower will leak into the string sealant 1, regardless of whether the glass is installed near the shower room or not.
It penetrates into the side surface of 6a and accelerates its hardening, but that side surface was previously covered with a rubber dam.

As shown in FIG. 5, the cohesive sealant extruded by the pump is formed into a string with a certain shape and can be touched to some extent, so that the non-uniformity of the work can be reduced compared to the conventional work. The operator can finish the corners of the glass plate more uniformly. No spatula work is required and no spatula work is possible. The high viscosity string-like sealant has no stickiness, and the low viscosity sealant does not flow into the space formed by the rubber dam, which is the case in the past. The degree of high viscosity can be obtained by compounding as described above, and it is necessary that the string sealant sufficiently adheres to the primer 8 at the same time as the glass plate is attached to the flange point welded to the vehicle body. Furthermore, after curing, the adhesion and seal strength of the strand sealant is equal to or greater than that achieved using conventional low viscosity polyurethane sealants and primers. All methods described in the DeSantis patent are applicable.

In the finished installation state shown in FIG. 10, the glass plate 4 is slightly separated from the spot welded flange, although this is somewhat exaggerated, just as in the conventional case when no rubber dam is used. The cured sealant is elastic and has some flexibility between the joints. The string-shaped sealant maintains a constant shape even when it is extruded from the nozzle in an uncured state, so when using the conventional technology of semi-fluid sealant, the operator is responsible for supplying the material, installing it, and finishing the work with a spatula. Waterproof sealing performance is improved compared to the conventional method in which the sealant flows out toward the rubber dam around the glass plate.

With highly viscous extruded string sealants, the sealant is cohesive, so if the operator slows down the removal of the sealant from the nozzle, the sealant will appear buckled and the slowness will be readily apparent. . Since the string sealant has cohesive properties, there is no need to scrape the sealant. In conventional products, spatula work is usually used to smooth out uneven application of sealant.

A summary of what has been said so far is as follows.

On the car assembly line, about 60 car bodies are washed away every hour, and windshields and rear windows need to be attached to them, so one car comes to the glass installation position every minute. Primer is applied to the perimeter of the edge-cleaned windshield and placed on a shelf in a drying rack, where there is no problem applying primer to one glass per minute.

The time previously required to attach the rubber dam is no longer necessary. Instead, a high-pressure pump is required, but a highly viscous sealant is pumped and
It is extruded from the nozzle in a matte, cohesive string, with a shape determined by the nozzle opening shape, and has a significantly higher tensile strength than liquid or semi-fluid materials. The extruded sealant string forms a hardened rubber string with a flat bottom and is attached to the perimeter of the primed glass. The worker operating the nozzle quickly and evenly applies the sealant in a string around the periphery of the windshield and rear window glass.
Even if the string-like sealant is not placed in the correct position, all you have to do is gently press it with your finger to the correct position, and if the operator changes the speed of movement between the nozzle and the glass rim, the operator will immediately notice and the work can be done cleanly. . The glass with the string sealant is then placed on the welded flange around the mounting opening, and the string sealant supports the weight of the glass without protruding into undesirable places, while at the same time avoiding any irregularities on the flange surface. The string-like sealant is flexible enough to uniformly contact the flange. If necessary, you can press it down a little with your hands. Because both sides of the string sealant are exposed to atmospheric moisture, curing occurs quickly and rapidly.

In addition to the cost savings of not having to use a rubber dam, the strong adhesion of DeSantis sealant eliminates the need for difficult cleaning procedures that can sometimes be impossible to clean. Thanks to this string-like sealant, it disappears.

Once the sealant is cured, the glass pane becomes one with the undercarriage flange, providing the same strong adhesion and shear tensile strength as DeSantis' low-viscosity sealant. The glass plate becomes a structural part of the car body, allowing the amount of metal used in the car body to be reduced. This configuration has passed current crash tests without the glass panes coming off.

In addition to this strength, it also has the elasticity of a low viscosity sealant. This provides the sealant with some flexibility to protect the glass pane from deformations that occur in the vehicle body during driving.

Since the shape of the string-like sealant initially placed on the glass plate is constant, the safety against waterproofing is high. In the final state, the sealant is uniformly adhered to the periphery of the glass.

Vehicle bodies with fixed side windows can also be fitted with glass using the invention. In this case, there is no problem with supporting the weight of the glass, but there is a problem with handling the sealant cleanly. As has been used up until now, low-viscosity sealants do not flow or drip under their own weight, but they easily stick to the car body even when lightly touched. According to the present invention, such a problem does not occur because a high viscosity string sealant is used.

The values actually used for the extruded string sealant are as follows.

A polyurethane moisture curable sealant of the composition described above has a pressure of 0.104
20 grams are pushed out from the inch outlet.
It was formulated to a viscosity requiring 342.6 to 355.3 seconds. The strands were formed by extruding this material and sealed using DeSantis' isocyanate-reactive primer, the system of this patent. The seal was tested and exhibited a tensile strength of over 900 pounds per square inch, 500% elongation to failure, a Shore A value of 60-65, and the seal was also resilient.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the windshield installation position on an automobile assembly line, and also shows the glass plate installation equipment and the shower room for conducting waterproof tests after glass plate installation. A perspective view showing a windshield glass plate mounted on a typical rotary table used in the glass plate direct mounting method in order to easily apply a primer to the periphery of the plate. The cross-sectional view in Fig. 4 shows an ordinary drum can delivered from a sealant manufacturer to an automobile manufacturer, and the string-shaped sealant of the present invention is extruded onto a glass plate, as shown in the figure, using a rotating table. FIG. 5 is a front view of the pump device with a flexible conduit connected to a nozzle; FIG. Fig. 5 is a cross-sectional view taken along the line -, and Fig. 7 is a suction cup type glass retainer that is normally used, which is omitted from this figure for the sake of simplicity. A perspective view showing the installation process,
Figure 8 is a sectional view taken along the - line of Figure 7;
The figure is a perspective view showing a state in which the windshield is attached, and FIG. 10 is a sectional view taken along the line - - in FIG. 9. In the drawings, numeral 1 is a car, 3 is a worker, 4 is a windshield, 8 is a primer (coating),
15 is a pump plunger, 16 is a sealant, 16a is a string-like sealant (string-like body), 16b
17 is a flat bottom surface, 17 is a nozzle, 21 is a flange of a glass plate attachment opening, and 22 is a worker.

Claims (1)

[Scope of Claims] 1. A method of attaching a glass plate directly to an opening having a periphery flange into which the glass plate is attached, the method comprising: applying an isocyanate-reactive primer to the periphery of the glass plate, and the sealant being extrudable by a pump. However, the string-like sealant coming out of the nozzle is cohesive and has a shape determined by the nozzle shape, so that it has a 0.104-inch opening at a pressure of 60 pounds per square inch, so that it has virtually no adhesive force under the pressure of its own weight. A moisture-curable polyurethane sealant whose viscosity has been adjusted so that it takes 300 seconds or more to extrude 20 grams is extruded from a nozzle using a pump, and while extruding the string-like sealant, it is applied to the top surface of the primer at the periphery of the glass plate. placing the string-like sealant, and attaching the glass plate to the opening by pressing the string-like sealant against the flange so that at least an inner surface of the string-like sealant is exposed to moisture in the atmosphere and cured; A method for directly attaching glass plates. 2 The opening and the flange are inclined so that the weight of the glass plate applies pressure to the extruded string-like sealant, and the string-like sealant alone supports the weight and creates a gap between the flange and the glass plate. The method according to claim 1, comprising: 3. The method according to claim 1 or 2, wherein the string-like sealant is extruded to have a cross-sectional shape with a flat bottom surface that rests on the peripheral edge of the glass plate. 4. Claims 1 and 2, wherein the glass plate is a windshield glass or a rear window glass of an automobile.
Or the method described in Section 3.