JPS604373B2 - stator assembly - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the adhesion of rod-shaped stator elements such as stator or stator elements, and in particular to the adhesion of such stators to specially formulated post-adhesive poly-IJ olefin copolymers.

Automatic nailers, especially those that are pneumatically operated, are relatively new machines in the construction industry.

However, it is widely used and its market is expected to expand rapidly. This automatic nailing machine requires that the nails be fed into the nailing machine in a timely manner and that the nails be held in a predetermined configuration so that the nails can be properly processed in the nailing machine. do.

In some cases, the planned arrangement form is a nail stack (cape ilst).
ack). This is exactly the same concept as the belt-held cartridges that feed heavy machine guns. Thus, the meaning of "processing J" is that the nails in the stack must be moved into the chamber of the machine and into the firing position without being contaminated.The device used to feed the stack is a spring-loaded device. (Actually, the technical idea of the present invention is
If a relatively strong polyolefin-based adhesive is used that is specially formulated to adhere to brass, it can be utilized to adhere machine gun bullets if desired. . ) Most nail stacks on the market today utilize hot melt adhesive to bridge the gaps between adjacent nails in the stack.

Paper strips are placed on one or both sides of the stack. Although such strips are necessary to increase the strength of the nail stack, they also contribute to improved appearance. The stacks prepared by these known techniques have several major drawbacks.

Some of these drawbacks are: (i) When exposed to the low temperatures common in outdoor construction, the bond undergoes brittle failure when dropped or loaded, resulting in further stack failure.

(ii) The adhesive will peel off from the glue during the firing process with sufficient velocity, not to mention additional cleaning problems.
It also raises safety issues.

(iii) A portion of the paper strip with an area larger than the nail head often gets caught on the nail and becomes lodged under the nail head, so that it has to be manually removed before the final plastering stage. ,etc.

Thus, the time has come when the automatic fixing machinery industry will be of great importance. Improvements that can be made to the unresolved shortcomings of currently commercially available nail stacks themselves will further increase industry growth potential. Furthermore, there are also related problems in the field of use in either automatic or manual dispensers used in a wide variety of applications.

These conventionally form a stator assembly having a plurality of rod elements firmly adhered to each other in adjacent, planar and parallel relationship.

Typically, for bonding, the wire is cleaned in a solvent bath, dried, and then placed in an adhesive tank. In the past, nitrocellulose has also been used as an adhesive for bonding rod-like or wire-like elements of stators, such as nails.

It's not a particularly effective adhesive. Moreover, it is applied from a solution of nitrocellulose with a solvent. The solvent is removed by passing the wire through a series of heaters (ovens). The solvent is not recovered (recycled) and escapes into the atmosphere. This presents challenges due to increasingly stringent solvent and emission standards imposed by ever increasing government enforcement agencies. The present invention includes a stator assembly which is an assembly of rod-shaped stator elements suitable for use in an automatic dispensing apparatus for dispensing stator elements such as nails or stubs.

These elements are held in place in their intended configuration by a special adhesive polyolefin composition. It has been discovered, and this discovery forms the substantial basis of the present invention, that it is possible to produce a stator which is significantly more advanced than the prior art and which is very useful.

Essentially, the gist of the invention is a stator arranged in a special configuration and held by special adhesives and techniques. In particular, the novel stator of the invention comprises a plurality of stator elements, e.g. be. These elements are held firmly in a predetermined specific arrangement and relationship by an adhesive, mostly C2-C8 polyolefin graft copolymer, used as tape, film, or powder, to form the stator.

The term "copolymer" as used herein includes polymers having two or more monomers.

One preferred feature is that the binder, when used as a tape, is a strip of predominantly 02-03 polyolefin copolymer with a 1-40 mil, preferably a 5-40 mil.
30 mils, most preferably 6 to 20 mils thick and sufficient to cover a stator element, such as 5 to 75%, preferably 20 to 60%, most preferably 30 to 40% of the length of the nail shank. including those with wide widths. Most preferably, the tape covers both sides of the stator assembly, such as the nail stack.

It is preferred that the polyolefin copolymer be grafted rather than randomly copolymerized (but not limited to grafting) with the reactive compounds described herein.

The content of crosslinking agent components, such as grafts, is about 0.12 to 20%, preferably 1 to 1%, and most preferably 2.0 to 8% by weight of the total polymer. Preferably, the adhesive component of the composition, such as the graph portion, is preferably an unsaturated mono- and carboxyl-containing acid (C3-C,o) having at least one olefinic unsaturation, anhydrides, salts of the acid, etc. , esters, ethers, amides, nitriles, thiols, thio acids, glycidyl, cyano, hydroxyglycols and other substituted derivatives.

Preferred examples of such acids, acid anhydrides, and derivatives thereof include maleic acid, fumaric acid, 3,6-endomethylene-Δ4-tetrahydro, phthalic anhydride, itaconic acid, citraconic acid, acrylic acid, acrylic acid. These include glycidyl, methacrylic acid, glycidyl methacrylate, cyanoacrylate, hydroxymethacrylate, polyester acrylate, acrylic anhydride, sodium acrylate, calcium acrylate, and magnesium acrylate.

Other useful unsaturated grafting monomers include substituted styrenes, acrylonitrile, vinyl chloride acrylate, dimethylaminoethyl acrylate, vinylpyridine, vinylpyrrolidone, vinylether copolymers,
These include maleic anhydride-styrene copolymers, acrylamide, and strained ring Diels-Alder adducts such as ethylidene norbornene. Acrylic acid and glycidyl acrylate are particularly preferred monomer grafting agents.

While random and graft copolymers can be prepared by known techniques, a particularly preferred technique for preparing the preferred graft copolymer binder of the present invention is described in Italian Patent No. 953,632
No. 2488).

It is recognized that a wide variety of polyolefin copolymer materials are suitable as long as they adhere well to the individual stator elements, such as rods or nails.

However, certain physical criteria that determine particularly preferred polyolefins are discussed below. Such polyolefins provide stator assemblies of great commercial value.
Above all, the essential requirement is that the tape has a suitable strong axis or bending strength, for example 1.8 to 0. Preferably 1.5 to 0.
5, most preferably between 1.20 and 0.6 ASTM D79
It is manufactured to have a 0 secant bending modulus (psi x 1).

o The 790 test gives an indication of the malleability of the adhesive binder. When the secant bending modulus is high, the material is rigid, and when it is low, it is flexible. Then, the secant bending modulus is the upper limit of 1.
If it is higher than 8 x 1 psi, the material may break during storage, but if it is lower than the lower limit of 0.5 x 1 psi, the binder will not separate properly from the nail during nailing, and
You'll end up getting stuck in the nailer. Preferably the material is 0.6
Has an ASTM D250 Izod impact strength (room temperature, feet/pounds per inch notch) of ~no failure, preferably 1.3 ~ no failure, and most preferably 1.5 ~ no failure. -40~75pm C, preferably -29~
Over a temperature range of 55°C, most preferably -23° to 44°C, the Izod impact strength without /ch ranges from 6 to no failure. The D25 test indicates the crushing strength of the binder material at low temperatures. The impact strength of the material must be sufficient to allow the nail assembly to maintain its integrity during operation in the nailing machine. Lower limit of 0.
6 is determined from this point of view, and the upper limit is one that does not break under the test conditions of ASTM D256. Another important criterion is ASTM D638 tensile strength, which measures 60
00-1500psi, preferably 4000-1700
, most preferably 3000-1800. The tensile strength must be sufficient (greater than 1500 psi) to handle the stator assembly in a normal manner. However, if it is greater than 6000 psi, it becomes difficult to break the binder and separate the individual nails during nailing. Furthermore, the adhesion force must be at least 3 to 6 steepness so that the grafted binder adheres to the stator, i.e., when it is nailed and even afterwards. , preferably 10-30,
Most preferably 20 lb/in2.

This is to ensure that the polymeric material does not flake off the surface. That is, during nailing, the binder always separates from the assembly while remaining attached to the individual nails, so that it enters the object together with the nails and does not remain in the processing area or accumulate under the nail heads. 3-6
The 0 psi range satisfies such requirements.

Outside this range, the binder will peel off from the nails or be unnecessarily too adhesive. For nail stacks, a very crude but practical test is performed on a nail stack stator assembly of the present invention (approximately 30-40 mm) as shown in FIG.
falling from a height of approximately 4 feet (approximately 1.2 feet).

The binder composition is considered to have satisfactory performance if it does not break down. Furthermore, the polymeric tape material must not fracture when the individual stator elements of the stator assembly are driven into various materials for the purpose of actual fixing.

In particular, in the case of nails, the nails themselves have to penetrate the driven material and carry the grafted tape, and at the same time the adhesion between the tape and the nails is limited by the actual automatic nailing stage. It must be strong enough so that it does not separate during the time.

Not only is the stator assembly of the present invention extremely useful for use in automatic stator dispensers, but the present invention also allows the stator assembly to be manufactured much more easily than those of the prior art. It has very important advantages. Thus, a grafted polyolefin tape that meets the physical and other criteria described herein comprises:
Nails or other materials capable of adhering strongly to the surface of the stator element can be applied to the stator element by at least one very convenient method.

One of these methods is to assemble 〈〈 in its predetermined arrangement.

Place the tape on the surface of the nail and heat the entire assembly sufficiently, either by heating the nail or placing the assembly in an oven, so that the tape will firmly adhere to the surface of the nail after curing. Become quite soft and fluid. This also preferably allows some of the tape material to flow into the gaps between adjacent nails of the assembly. Such flow helps maximize the surface area of the nails that adhere to the binder, such as the tape. The exact conditions will vary somewhat depending on the particular stator element to which the tape is attached and the exact composition of the tape. Alternatively, the tape itself can be extruded directly while the stator element is held in its intended location in a jig or other device.

The flexible extruded tape is deposited on the surfaces of stator elements, such as nails, and builds up the strength of these surfaces upon cooling. The nails can also be preheated to a predetermined temperature so that the extruded tape does not cool so quickly that it cannot initially adhere properly. Maximum adhesion can be improved by quenching the molten tape after heat soaking the stator elements for a few minutes, but quenching is not recommended since less than the maximum adhesion is entirely adequate for the purposes of the present invention. is not necessary. Although the polyolefin copolymer tapes described above are the preferred means for warming stator elements to form the stator assemblies of the present invention, other techniques utilizing copolymers may also be effective.
It can be used to form new stator assemblies.

One method that can be used is to coat the individual stator elements with a thin partial or complete coating of adhesive polyolefin copolymer. Coating can be carried out by solution, extrusion or powder techniques. The coated elements are then placed in a predetermined position by any convenient means as described above, such as a jig, subjected to sufficient heat to cause coating flow, and then allowed to cool naturally or forcefully to obtain a stator assembly. .
The stator elements are also set in a predetermined configuration and "coated with polyolefin copolymer powder electrostatically or in a fluidized bed, heated to cause movement of the coating, and then allowed to cool naturally or forcedly so that the stator You can also get aggregates.

Although the above technique can be used with a stacked stator assembly, it is particularly preferred when the stator assembly is also a planar structure straddle for a nail gun.

The assemblies and techniques of the present invention also encompass both nail arrangements and nail stacks, which differ significantly in their properties, and techniques that are particularly suitable for forming nail stator assemblies. There is ample need for discussion.

Straddle stator assemblies with good distribution properties can be most conveniently prepared by first arranging a large number of strut elements in parallel and planar relationship in contact with one another.

Eventually, a film or binder (as described herein) will be placed on top of the straddle. The nails are also heated in an oven or directly sufficient to soften and flow the film.

Cooling also holds the nails in the intended position due to the adhesive properties of the film. Alternatively, the film can be melt extruded directly onto heated studs or other stator elements.

Tape can be used as well. Also, in many fixing operations, the functionalized binder copolymer materials used in the stator elements are used due to the interaction of the functional groups of the binder, e.g. carboxyl groups, with the functionality of the material to be fixed, i.e. wood, steel, etc. Adheres to the surface of the material to be fixed. See Figure 3. In the drawings, Figure 1 is
and a portion of a stator assembly 10 (nail stack) with adhesive polyolefin tape 14.

The tape is as described in the example below which is adhered to the nails to hold them in a predetermined position. Figure 2 shows transverse line 2
-2 is a sectional view of FIG.

FIG. 3 shows two pieces of wood held together by stator elements (nails) of a nail stack.

FIG. 4 is a photograph of a portion of an actual nail stack according to a preferred embodiment of the invention.

The head of the nail has been cut off. Particularly preferred compositions for use in articles of the invention include the plastics and elastomers listed in Table 1 below.

Table 1 * (Including thermoplastic impact-resistant grades and block polymer impact-resistant grades), and can be used without additives.

Preferred compositions of the invention contain a sizable elastomeric component.

This plays an important role in the rheology of the adhesive binder as well as in the magnitude of the adhesive force. elastomeric EPR or EPDM copolymer from 20 to 9% by weight;
Preferably from 40 to 8% by weight, most preferably from 50 to 8
% by weight of etherene.

It is generally preferred that they have a highly crystalline component, eg, a high green strength. The type and amount of elastomer is not critical as long as the final composition has the specified proportions. Blends of ethylene and propylene polymers can also be used as plastic components.

They contain 50-9% by weight of polypropylene and 50-1% by weight of polypropylene.
% by weight of polyethylene, preferably 50-85% by weight
of polypropylene and 15 to 5% by weight of polyethylene,
Most preferably 60-75% by weight polypropylene and 4
Contains 0-25% by weight polyethylene. The polyethylene component can be of high density or low density. The grafted or copolymer portion of these polymers is preferably acrylic acid or glycidyl acrylate and is present in an amount of 0.2 to 2% by weight as described above.

Although the polymer can be grafted directly to the desired degree, it is convenient to first graft the polymer to a relatively high level and then blend it with the ungrafted polymer to the particular desired level. This is particularly useful when relatively low levels of grafting are required. Although the adhesive binder compositions described herein adhere very well to all ferrous metals and most non-ferrous metals, although generally included within the binder compositions described, special compositions may be and is necessary to obtain adhesion to copper-containing alloys.

The binder compositions that must be used to effectively bond copper stator elements or other steel articles or copper-containing alloys are as follows.

Generally, a blend of 60 to 90%, preferably 80 to 95%, most preferably 85 to 9% by weight of low density polyethylene with the remaining proportion of butyl rubber or polyisobutylene, the balance being from about 0.02 to 2 wt%, preferably 0.1 to 1 wt%, most preferably 0.2 to 1 wt%
Grafting with 8% by weight of acrylic acid or glycidyl acrylate was found to adhere well to steel or copper alloy substrates.

Polypropylene containing a small amount of ethylene polymer component grafted with glycidyl acrylate is particularly effective in obtaining maximum copper adhesion. It has been found that in formulating the adhesive binder of the present invention, there is a delicate trade-off between complete contact of the binder with the stator element and melt strength.
The final composition must be satisfactory in all respects. Melt strength is important because the binder, when melted, may be subjected to dynamic conditions.

It must also be capable of retaining its integrity when stressed and moved while molten. On the other hand, the effectiveness of the adhesive depends on the maximum contact between the binder and the stator elements. Therefore, while the binder is melting,
Must be somewhat fluid for best results. A rough measure of these properties can be obtained by measuring either the melt index (MI) or the melt flow rate (M'R).

The above MI and MFR are considered to be mutually convertible in this specification. Generally, the novel adhesive binders of this invention should have an MFR of about 1-30, preferably 5-20, most preferably 8-12.

When blending an elastomer into a given plastic, the M'R tends to be lower than the MFR of the starting plastic.

Therefore, plastics are generally manufactured with a higher MFR than desired in the final composition (eg, by peroxide decomposition). A wide variety of elastomers can be used to blend with plastics.

These are mostly amorphous materials, which provide additional sacrifice for absorbing impact forces, especially at low temperatures, when the plastic component approaches or exceeds its glass transition temperature. Generally, elastomers are chosen for their convenience in blending with plastics, especially when extruder mixing is the only option available.

Also, saturated elastomer or low unsaturated elastomer (E
PR, EPDM) are usually highly unsaturated elastomers,
For example, it is more preferable than natural rubber, polybutylene, etc.

The invention will be further illustrated by the following examples, but is of course not limited thereto. Example 1 In a preferred embodiment, the stator assembly of FIG. 4, which includes a plurality of nails held in a flexible predetermined configuration, was manufactured by the following technique.

Place the nails in the jig in the planned location. 1-22 MFR
% by weight of high molecular weight isotactic polypropylene 6 with ethylene-propylene elastomer (E
MD-492, obtained from Exxon Chemical Company), and each about 10 Mm
Grafting 6 mils thick and 0.95 skin wide, consisting of grafting with 4% by weight acrylic acid by the method of Japanese Patent Publication No. 55-22488 mentioned above to give a grafted adhesive composition having R. A strip of polyolefin tape was used to hold the nail in place.

Polyolefin tape has 200 sifters per inch notch. /lb. ASTM D638 tensile strength,
ASTM D79 dark U-wire bending modulus of 75,000 psi and 1.7 ft. at room temperature. /1. /in. It has an unnotched Hyzod impact strength (ASTMD256) of . Place this tape on top of the same arrangement as described in FIG.

The nail with tape was heated from above to a temperature of 220° C. for 3 minutes. At the same time, the same tape was applied to the opposite side of the nail placement with the same adhesive method conditions. The resulting assembly was cooled to room temperature and tested for adhesion to the tape.

Saddle strength measurements ranged from 15 to 30 pounds per inch width. After drop testing the resulting stack assembly, it was sent to Paslode Division of Sigurd Corporation.
The test was carried out on a pneumatic movable stitch machine manufactured by OnofSi Mochi Corporation. The test results show that the nails performed very well in the pneumatic nailing machine. The results were much better than those obtained using nail stacks glued by the conventional twill technique. Example 2 The same technique as in Example 1 is repeated except that instead of the glass fiber reinforced thermoplastic rods which can be used as stator elements are used.

Example 3 Repeat Example 1 except that instead of steel nails, aluminum rods are used which can be used as stator elements.

Example 4 Copper wire was used instead of steel nails, and the tape was a low density ethylene polymer containing 1% by weight of butyl rubber, the total composition of which was grafted with 3% by weight of acrylic acid. Repeat Example 1 with one exception.

Example 5 A crossnail assembly of the present invention is manufactured by arranging nail elements in side-by-side contact and planar relationship.

A thin film (approximately 3 mils) of the binder of Example 1 is coated on an element heated to a temperature above the temperature of the binder. Example 6 The same procedure as Example 5 is repeated except that the element is coated with a fine powder prepared from the binder of Example 1.

The particular embodiment described above is for a nail stack stator assembly in which truncated nails are the stator elements.

Other types of nails can also be used in nail stacks if they are adjusted to fit that particular type.

For example, drywall nails have a full head as opposed to a nail with a half-headed nail. Therefore, they are naturally placed separately in the stack. Preferably, when the tape is used in drywall nail stacks, a portion of the tape approximately mid-span between each nail is cut out and marked or knurled.

This is so that the tape can be cut without each nail taking up more than its share of tape binder.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of a representative portion of a stator element, such as a nail, constituting the assembly of the present invention, and FIG. 2 is a cross-sectional view of the assembly taken along line 2--2 in FIG. 3 is a diagram showing a stator element of the invention embedded in two pieces of wood joined together, and FIG. 4 is a photograph of an actual embodiment of the invention. FIG. l. FIG. 2. FIG. 3. Bonito thighs, bonito flies, dark seaweed

Claims (1)

[Claims] 1. An assembly comprising a plurality of stator elements arranged in a predetermined arrangement and held in said arrangement by a flexible binder composition, wherein the binder composition comprises 1 to 20 stator elements.
A blend of C_2 to C_3 polyolefin materials having a MFR of
0 to 90% by weight of polyolefin plastic and 70 to 10% by weight of an elastomer selected from ethylene-propylene copolymer, polybutylene and polyisobutylene, and the composition contains 1 to 20% by weight of C_3 to C_1_0. in an assembly grafted with a graft component of an unsaturated carboxylic acid or a glycidyl derivative thereof, and further wherein said composition is firmly adhered to the surface of said stator element due to the adhesive functionality imparted by said graft component. , the binder composition is applied to each stator element without separating from each stator element when the portion of the binder adhered thereto is separated from the arrangement and driven into an object for fixation. As attached to the child element, the following physical properties, (i) 1
．． 8~0.5 secant bending modulus (×10^5psi
), (ii) 0.6 to Izod impact strength without breaking (
room temperature), (iii) a tensile strength of 600 to 1500 psi, and (iv) an adhesion strength of 3 to 60 psi.